At one time declining significantly due to the use of persistent pesticides such as DDT, the Osprey’s population reduction played a role in the banning of some of these chemicals, and the population subsequently rebounded. In recent decades, Ospreys in many areas have adapted to using artificial nest substrates such as towers and utility poles.
Old Osprey nests are used for nesting by many other species of birds, including hawks, owls, herons, and gulls. A few birds in some areas, such as House Sparrows, Tree Swallows, and European Starlings, even build their nests within active Osprey nests, and are ignored by the Ospreys.
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Description of the Osprey
The Osprey is mostly dark brown above and pale below, with dark inner flight feathers contrasting with pale wing linings. The wings are long and narrow, with a kinked shape obvious in flight. The dark head has a wide, white supercilium. Length: 24 in. Wingspan: 65 in.
Seasonal change in appearance
Juveniles are buffier below and have pale mottling above.
Ospreys inhabit lakeshores, rivers, and coastal areas.
Ospreys eat small fish.
Ospreys forage by flying over water, hovering to spot prey, and plunging into the water to grasp fish with their talons.
Ospreys breed from Alaska across Canada to the Atlantic Coast, and in parts of the northwestern and northeastern U.S. They are resident in the southeastern U.S. Migratory birds winter in the southernmost U.S. south to South America. They also occur nearly worldwide. The North American population has increased in recent decades.
Bald Eagles sometimes steal fish from Ospreys.
Ospreys once declined dramatically due to the use of the pesticide DDT, but after its use was banned, they began to recover.
Ospreys have proportionally large wings to help lift them from the water while carrying a fish.
The call consists of shrill whistles.
- Immature Bald Eagles have a dark throat and straight wings.
The Osprey’s nest is a platform of sticks and is lined with finer materials. It is placed in the top of a large tree, or on a utility pole or artificial nest platform.
Number: Usually lay 3 eggs.
Color: Whitish with darker markings.
Incubation and fledging:
The young hatch at about 38 days, and fledge at about 51-54 days, though remaining dependent on the adults for some time.
Bent Life History of the Osprey
Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.
Bent Life History for the Osprey – the common name and sub-species reflect the nomenclature in use at the time the description was written.
PANDION HALIAETUS CAROLINENSIS (Gmelin)HABITS
The osprey, as a species, is widely distributed throughout the world and has been divided into five subspecies. Our race breeds in North America but. wanders to Central and South America. It has a wide range over most of this continent, but, as a breeding bird, it is rare or widely scattered throughout most of this range. In a few favorable localities, mainly along the Atlantic coast, it is very abundant and breeds in several more or less dense colonies. As it lives entirely on fish, it naturally prefers to live in the vicinity of the seacoast or near some large body of water, lake, or stream, where it can find an abundance of its finny prey. Given this food supply, it makes little difference to the osprey what its surroundings are. It is equally at home near the shore of some remote wilderness lake, on timbered or open islands along the coast, in the valleys of inland streams, in open farming country, or even close to houses. In the last two localities it is jealously protected and often encouraged to breed by placing cart wheels or other supports for its nest in trees or on poles. In the region where I am most familiar with it, it has become a common dooryard bird, almost a domestic pet., and consequently very tame.
The history of the status of the osprey in Massachusetts is rather interesting, as illustrating how little some of the early writers on local ornithology knew about the birds of the State outside of the limited regions with which they were familiar. Dr. J. A. Allen (1869) wrote: “It seems at first a little strange that this noble bird should not be found breeding anywhere on the Massachusetts coast. The present puny second forest-growth affords it no suitable breeding places, and this is no doubt the reason of its being now but a transient visitor here.” This remarkable statement shows lamentable ignorance of the nesting requirements of the osprey and a lack of acquaintance with the forests of Bristol County, which in those days were far from “puny.” This error was repeated by Minot (1877) and Stearns (1883).
It was my old field companion, Frederic II. Carpenter (1887) who first called our attention to the large breeding colonies of these fine birds in southern Massachusetts. It was he who first introduced me to these interesting colonies, with which we have kept in close touch ever since.
The changes in the distribution of the nesting birds during the past 50 years, in the area covered by our observations, are also interesting. When our records began, in 1882, there were over 80 occupied nests in the rather limited area that we hunted, on foot, in Rehoboth, Seekonk, and Swansea in Massachusetts and in Warren and Barrington in Rhode Island. As time went on, we enlarged our field and discovered a number of outlying nests in neighboring towns, both north and south of the region named. The northernmost nest, north of Taunton, was 18 miles from the nearest salt water; and some of the Rehoboth nests were 12 miles inland. The interesting point is that these inland nests have been gradually disappearing, until now not one of the 81 nests recorded in 1882 is in existence. The ospreys are now all concentrated near the shores of Mount Hope and Narragansett Bays and their tributaries. What caused this wholesale evacuation is a mystery. Considerable egg collecting was done in certain parts of the area, but no more than, if as much as, in the area where the birds still breed. There are just as many suitable trees as ever, and many perfectly sound nesting trees have been abandoned. There may be fewer fish in the inland ponds and streams, though there has been no noticeable increase in pollution. The only answer seems to be that the birds have decreased in numbers, from some unknown cause, and the remaining birds are concentrated where there is a better food supply and where they are more rigidly protected. In the area that we now cover, there are between 50 and 60 pairs of birds nesting, where there were at least twice that number 50 years ago. Formerly we could visit between 30 and 40 breeding pairs in a day on foot, but now our best recent record is 56 pairs seen with the help of an automobile.
Spring: Throughout all the northern part of its range the osprey is migratory. In much of Florida and in the Gulf States the osprey is present all winter, but C. J. Pennock tells me that it is absent from northern Florida, Wakulla County, “from about the middle of November until early February.” Arthur T. 1tVayne (1910) says that it is absent from South Carolina “from December until very late in February.” Mr. Pennock’s earliest date for Delaware is March 16. In southern New England, the ospreys appear with considerable regularity during the last week in March; my earliest date is March 15, but Forbush (1927) has a record for March 7. Usually only a few individuals are seen here in March, the main body arriving during the first week in April. The males are said to precede the females. Their migrations are probably influenced by the movements of the fish on which they prey; we usually see them at about the time that the alewives, or herring, are starting to run up the rivers. In other l)arts of the country, their arrival is equally subject to climatic and food conditions. M. P. Skinner’s notes give the dates of arrival in Yellowstone National Park as ranging, over a period of seven years, from April 9 to 25.
Courtship: 1 believe that ospreys are mated for life, as is the case with many other large birds. Dr. Harry C. Oberholser (1897) tells the following pathetic story, illustrating the constancy of a bereaved mate:
At a time when one of the birds, presumably the female, was on the nest, a bolt of lightning struck the tree, killing the bird and demolishing the nest. Strangely enough, the other osprey when returning only to find his home desolated, took up his station upon the top of one of the uninjured trees close at hand, and throughout the remainder of the summer was seen day after day, month after month, keeping his lonely vigil, apparently mourning the loss of his mate. PIe remained until late in September, but at the time that the other ospreys departed he too disappeared. The next spring, however, found him again at his post, and throughout the whole summer he continued just as before; but in the ensuing autumn, joining the company of his fellow ospreys in their journey to time southland, he departed, this time to return no more.
But such constancy is not the invariable rule. I have known of several cases where one of a pair has been shot and the survivor has secured a new mate. I also knew of a case where both of a pair were shot and a new pair appropriated the nest.
As soon as the ospreys arrive on their breeding grounds they inspect the old nest and begin repairing it. One bird, probably the female, stands on the nest, and receives and arranges the material brought in by her mate; it is interesting to see these great birds flying home with a long string of seaweed or cornstalks trailing out behind. Mrs. Irene G. Wheelock (1904) says that the osprey breaks off the dead twigs from a tree, sweeping down on them and seizing them in its feet.
All is activity in the colony, as new birds are arriving at intervals, looking up their old nests or seeking locations for new ones. As most of the birds are already mated, courtship is mainly a nuptial display, an expression of joy at their home coming, or an exhibition of exuberant spit-its. It consists mainly of aerial gymnastics in which both sexes indulge, chasing each other in swift pursuit-flight, soaring, scaling, circling, dodging with rapid turnings or quick dashes downward, as they sweep, now low, now high, in wide circles. Several pairs are often seen in the air together, and sometimes trios, all screaming their notes of love or excitement.
Copulation is performed on the nest or on a branch of a tree; the male stands on the back of the female, balancing himself by waving his wings, and making connections for a few seconds.
William Brewster (1925) saw what was probably a male: mount to an Immense height above the Lake near Great Island, to drift slowly eastward over the forest, poising or hovering all the while on set or looselyflapping wings, uttering almost ceaselessly a shrill, screaming crce-crec-cree wholly different from the ordinary musical outcry of his kind. All this was kept up fuliy fifteen minutes. Of course it represented the characteristic love-flight of the Osprey, often witnessed at the Lake in early spring, and not unlike that performed hy several other species of Hawks found in New England. Finally a female Osprey appeared, swinging around and around in wide circles a thousand feet helow tl~e other bIrd. He, however, continued to hover, flutter, and scream at his former level.
Nesting: What was once, probably, the largest known breeding colony of ospreys formerly existed on Plum Island at the eastern end of Long Island, N. Y. Charles Slover Allen (1892) gives a very interesting account of this colony, which had been protected for many years by the former owners, the Jerome family. When Mr. Allen first visited this island in 1879, Mr. Jerome “claimed that fully two thousand nightly roosted on the island, and that over five hundred nests had been built there.” But Mr. Allen “finally reduced these numbers one half.” In 1885, this island “was sold to a syndicate who planned the construction of large hotels and cottages; since then all has completely changed.”
Probably most of the ospreys from Plum Island moved over to Gardiners Island, only a few miles distant, which now holds the largest breeding colony of which we have any record. The size of this colony has been variously estimated, but I doubt if any accurate census has ever been taken. Good descriptioiis of this colony have been written by Dr. Frank M. Chapman (1908), who estimated the number of nests as 150 to 200; by Clinton G. Abbott (1911), who estimated 200 nests; and by Capt. C. W. R. Knight (1932), who thought the number exceeded 300. Gardiners Island is about 7 miles long and 3 miles wide and contains about 3.000 acres.
Our scattered colony, in southern Massachusetts and eastern Rhode Island, could now be covered by a circle 8 miles in diameter, and contains about 60 occupied nests, possibly a few more; it formerly covered more than twice this area and contained much more than twice this number of nests.
Bendire (1892) mentions a colony on Seven Mile Beach in southern New Jersey, in which “several hundred pairs have nested every season.” In other parts of the country the colonies are usually smaller, or more scattered. Mr. Abbott (1911) found a colony of 30 nests at Great Lake, N. C., in 1909.
Donald J. Nicholson tells me that in 1910 there were at least 75 occupied ospreys’ nests in the cypresses around Lake Istokpoga in Florida; and in Volusia County “possibly hundreds of their nests can be found in the cypress swamps near Maytown, 30 being visible from a lofty cypress.” William G. Fargo writes to me of a colony of 12 or more nests that he found near Old Tampa Bay, Fla., “of which at least nine were within an area of about 100 acres.”
The region with which I am most familiar, southern Massachusetts and eastern Rhode Island, is largely an open farming country, with considerable heavily wooded territory scattered through it, with numerous streams and small lakes and with many large residential estates near the shores of the salt-water bays. Formerly many ospreys nested in the wooded sections, far from human habitations. The nests were usually placed in the largest trees they could find, tall solitary white pines, or large oaks on the edges of the woods, and generally not far from some lake or stream, where the fishing was good. Comparatively few were more or less hidden within the woods, in almost any kind of large tree, or on the top of some large dead stub. These woodland nests have nearly all disappeared, except in a few large groves near the shores, where they are protected, but even these are decreasing.
The nests in the open farming country and on residential estates seem to be the most successful and to last the longest. Here the ospreys seem to have no special preference for any species of tree and are not at all particular as to its height. Security and a good food supply seem to be all that they require. Sycamores, locusts, and elms figure most prominently in my notes; but we have also found nests in various oaks, ashes, tupelos, maples, red cedars, wild cherries, willows, pines, and even apple trees. Many of the nests are in partially, or wholly, dead trees; although the birds sometimes build in a dead tree, I believe that in most cases the tree is killed by the weight of the nest or by the saline character of the nesting material and of the birds’ food; I have known of many cases where the tree has died and fallen after the ospreys had built in it. Some of the occupied nests have been in trees standing in water; one such in a pond was so low that it could be looked into from a boat.
Many nests are built on poles near houses (p1. 97), a cart wheel or some other support having been attached to the top of it to hold the nest. Similar supports are often placed in trees by the landowners, who protect the ospreys and encourage them to nest near their houses or on their farms as picturesque features or because they are supposed to drive away other hawks. Ospreys often build on telegraph or telephone poles, where the cross arms and wires give good support, much to the annoyance of the linemen who have to remove the nests. Harry S. Hathaway (1905) says that “one pair in Bristol was so persistent in ‘sticking’ to the same pole after it had been pulled down that they built it up four times, and it was only after a ‘ground’ had been made by the wet mass in a rain, which set the pole and nest afire, that they deserted it.”
A better location, recently adopted, is the steel framework of a high-tension-line tower. Nests are also built occasionally on buildings or on unused chimneys. Mr. Forbush (1927) tells a remarkable story of a pair of ospreys that had a nest on the chimney of a vacant house. A new family moved in, removed the nest, and shot one of the birds. The survivor secured a new mate and rebuilt the nest. By the time that the birds were at last driven away, after repeated attempts to rebuild the nest, the chimney was found to be completely filled with rubbish. I once saw a nest on an electriclight transformer to which a white flag was attached. Several nests have been on unused windmill towers. Mr. Hathaway (1905) says: “One of the most unique situations that has come to my attention is a nest in Portsmouth, built on an old windmill, which has had the ‘floats’ blown off, and the nest is so placed that, when the rudder turns, the sitting bird, on her nest, swings round and round with every breeze.”
In our territory I have never seen a nest on the ground. The height above ground has varied from 10 or 15 feet, in cedars, locusts, or on poles, to 50 or 60 feet, in tall pines or elms; but most of the nests have been under 40 feet. The nests vary greatly in size; nests on artificial supports are usually very flat, from a few inches to a foot high, and they are not built up from year to year, as the tree nests are; the latter often increase to enormous size until they fall or break down the tree; the tallest one I have seen was built up to a height of 10 feet before the tree and all collapsed.
None of my earliest nests are still in existence. One nest that I first saw in 1891 was still occupied in 1935; it is in a locust, now dead. There are two others that I have recorded as occupied for 41 years, one in an elm and one in a locust. Another, still occupied in 1935, has been occupied for about 45 years, according to an interested neighbor; this is artificially supported in a locust close to a much-traveled road. A few other nests have lasted for 30 years or more, but most of them last for much shorter periods. Mr. Hathaway (1905) refers to a nest in this territory that has been used annually since “about 1780, and was until recently still occupied” by successive pairs of birds.
The foregoing remarks all refer to nesting habits in Massachusetts and Rhode Island. C. S. Allen (1892) describes some interesting nests on Plum Island, as foUows:
The first Fish Hawk’s nest shown to me by Mr. Jerome was fairly in his dooryard, close by his front gate, and only about fifty yards from his house. It was placed upon an old pile of fence rails, rotted to black mould in the center, but kept up by the yearly addition of fresh rails. Mr. Jerome said that to his kanwiedge this nest had been occupied every year for forty years. It likewise had been added to yearly until its bulk of sticks, sods, cow dung, decayed wood, seaweed, etc., would amount to at least three carloads, in addition to what had rotted and fallen to the ground. The nest was only seven or eight feet from the ground, so tbat by stepping on a projecting rail I could readily see the three beautiful spotted eggs within, which I promised not to disturb. Mr. Jerome could pass close to the pile of rails without the birds leaving the nest, while I could not get nearer than thirty or forty feet.
Out on the sandy meadow to the southward were what at a distance appeared to be two gigantic mushrooms about seventy-five yards apart. A nearer a~ preach disclosed the fact that they were cedar trees twenty feet high; the trunks were about one foot in diameter and without a limb for the first ten feet. The whole top of each tree was involved in a huge nest. These nests, Mr. Jerome said, bad been occupied every year for forty years, each year the Hawks repairing them and adding to their bulk. These nests were so unusually large that they are worthy of description. Each nest involved the whole tree, even to the lowest branches. At the base loose sticks, six to twelve feet In length, were spread out so as to form a projecting platform ten to fifteen feet in diameter forming complete protection from below. The base of the solid portion of the nest was about eight feet across, sloping up to the level top, which was about four feet across, and very firm and solid, and readily bearing my weight. The bulk of this nest was about equal to three cartloads. The central part of the nest consisted of a mass of sand and decayed matter from the old nests, much of which had fallen through to the ground. The base of the nest consisted of long sticks, oyster stakes, etc., loosely put together and extending beyond the longest limbs of the tree, making It over twelve feet in diameter. Each year for many years the nest had been repaired and built up with every kind of material that had been washed ashore or could be picked up In the fields. The center of the nest, nearly five feet high, was composed of clods and sand and the decayed remains of material added many years before.
Of the famous colony on Gardiners Island, Mr. Abbott (1911) writes:
Ospreys’ nests on Gardiner’s Island are placed In almost every conceivable situation. They are on trees by scores, both high up and low down; on rocks and boulders, whether on land or In the water; on sheds and buildings; on fences and walls; on piles of debris; on old stumps; on a floating wooden platform intended for the fishermen’s use: on a channel buoy; on sand-bluffs; on pieces of wreckage, driftxvood, and fish-boxes. The birds even attempted to build on the slender stakes supporting the fish-nets! In all of these varied nesting-sites, however, It will be noted that at least the suggestion of an eminence has probably first attracted the Osprey to the spot. Similarly, many of the ground nests are found to be very close to some prominent object: itself incapable of supporting the nest: such as a post, a notice-sign, a telegraph pole, or a pointed stone. The high, shelving beach, with its tempting piles of seaweed, probably appealed to some of the first ground-nesters as an “eminence,” and their offspring have come back and chosen a similar nesting-site. Al all events, in 1910 there was a succession of no less than twenty-two nests at intervals varying from eleven yards to three hundred yards along the beach, on the south-westerly side of Gardiner’s Island. Some of the most recent additions to the beach-nesting colony had certainly quite lost any instinctive attraction for an “emInence”; their nests being a mere scattering of sticks In the edge of the marsh-grass: in location suggesting more the humble home of the Tern than the eyrle of the noble Osprey.
In the southern Atlantic and Gulf States the ospreys nest very commonly in living or dead cypresses, about the shores of lakes, along the banks of streams, or on the borders of swamps. Some of these old stubs, which resist decay for many years, even when standing in water, offer ideal nesting sites.
In Florida I have seen many nests in such locations, as ~vell as in tall pine trees; most of the nests in pines range from 25 to 70 feet from the ground, but Mr. Nicholson tells me that he has seen them as high as 110 feet. In southern Florida, they often nest in low mangroves, 15 to 20 feet above the water, according to Mr. Pennock. Among the Florida Keys I once saw a nest built on the tops of some little low mangroves, with its base only a few inches above the water: we could look into it from a boat.
Mr. Skinner’s notes mention some interesting nests in the Yellowstone National Park. One of the most famous nests is on “Eagle Nest Rock”, a lofty pinnacle in Gardner Canyon; he says that this has been occupied: each year since 1875 at least, but one spring I found as many as seven adult osprey In its immediate vicinity. The nests at Eagle Nest Rock and In the Grand Canyon of the Yellowstone are on the tips of pinnacles of rock jutting out from the canyon slopes. As these are usually the only nests seen by visitors, they unconsciously form the opinion that all osprey nests are on rock pinnacles.
But this is not true, even for the majority of the Yellowstone osprey, for the original and most used sites are on the tips of dead trees, and on the tips of living lodgepole pine and spruce trees. In 1914, I estimated there were 25 nests In the Grand Canyon; adding in the Eagle Nest Rock site and all others there may be 30 rock pinnacle sites in Yellowstone National Park that are occupied by osprey nests. But there are twice as many tree sites as that around Yellowstone Lake alone.
He says he has seen the nests “floored with cedar bark. Often these osprey added a rim of green pine tips to their nest. in each case it looked like a large wreath of green laid on the nest floor, surrounding the eggs and sitting bird.”
Bendire (1892) writes:
The most picturesque nesting site of the Osprey I ever saw was located in the midst of the American Falls of Snake Biver, Idaho. Right on the very brink of these, and about one-third of the way across, the seething volume of water, confined here between frowning walls of basalt, was cleft in twain by a rocky obstruction which had so far withstood the ever eroding currents, and this was capped with a slender and fairly tapering column of rock rising directly out of the swirling and foaming whirlpool below. On the top of this natural monument, whose apex appeared to me to he scarcely 2 feet wide, a pair of Ospreys had placed their nest and were rearing their young amidst the never ceasing roar of the falls directly below them.
About the inland lakes of California the favorite nesting sites seem to be the broken tops of dead pine trees, sometimes standing lfl or near the water and sometimes several miles from it; some of these are very lofty, 75 to 112 feet from the ground and often inaccessible. But on the coastal islands, where there are no large trees, the ospreys build their nests on pinnacles of rock or on outlying rocks, where they are not easily reached. In Lower California they sometimes nest in the giant cacti, which offer firm support and discouragement to climber,s; on the islands here they build ground nests on the higher beaches.
The enormous nests of the osprey are made mainly of large sticks, sometimes 4 feet long or longer and as large as a man’s wrist, mixed with sods and almost anything that the birds can pick up. A~ they last for many years, with annual additions, the older material becomes thoroughly rotted, and the nests become heavy enough to break down any but the stoutest trees.
C. S. Allen (1892) records the following list of material that he l)ersonally observed in the nests on Plum Island:
Brushwood, barrel staves, barrel beads, and hoops; bunches of seaweed, long masses of kelp, mullein stalks and cornstalks; laths, shingles, small Pieces of boards from boxes; parts of oars, a broken boat-hook, tiller of a boat, a small rudder, and parts of life preservers; large pieces of fish nets, cork, and cedar net floats, and pieces of rope, some of them twenty feet in length; charred wood, sticks from hay bales, and short, thick logs of wood; a toy boat, with one sail still attached; sponges, long strings of conch eggs, and eggs of sharks and dogtish; a small axe with broken handle, part of a hay rake, old brooms, an old plane, a feather-duster, a deck swab, a blacking-brush, and a booliack; a rubber boot, several old shoes, an old pair of trousers, a straw hat, and part of an oil skin ‘sou’wester’; a long fish line, with sinkers and hooks attached, wound on a board; old bottles, tin cans, oyster shells, and large perixvinklo shells, one rag doll, shells and bright colored stones, a small fruit basket, part of an eel pot, a small worn out door mat; wings of ducks and gulls, sometimes with parts of the skeleton attached, and one fresh crow’s wing, as already related. A strange feature was the frequent presence of bleached bones from the pasture, as the ribs and long bones of sheep and cattle, and especially slteep 8kulls. Nearly all the old nests had masses of dried cow dung, and large pieces of sod, with grass still growing.
Others have noted similar interesting collections of materials in the nests, but Chester C. Lamb (1927) found some of the most unique nests on Natividad Island, Lower California; he says: “All the nests examined were made partly of Black-vented Shearwater wings, and of one nest seen, all except a part of the foundation was entirely made of wings.”
Eggs: Tbe osprey lays almost invariably three eggs, occasionally only two and more rarely four. T. E. McMullen’s series of 100 sets contains 12 sets of four and none of two. Griffing Bancroft’s series of 49 sets contains 4 sets of four and 11 sets of two. My experience has been that sets of four are less than 5 percent of the total. F. A. E. Starr tells me that he knows of a set of five, and Mr. Allen (1892) once found five in a nest On Plum Island. Reginald Heher Howe, Jr., (1895) reports a remarkable brood of seven young, only four of which survived. One of our pairs laid sets of four eggs for three years in succession and then laid a set of two. Another pair laid two sets of four, one in 1897 and one in 1902, with normal sets in the intervening years.
The eggs of the osprey are the handsomest of all the hawks’ eggs; they show considerable variation, and the coloring is very rich; a selected series of them is a great addition to an egg collector’s cabinet. I shall never forget my envious enthusiasm when a rival boy collector showed me the first fish hawk’s eggs I had ever seen. Nor could I ever forget the peculiar pungent odor that clings to these eggs after many years in the cabinet, a fragrant reminder of many hard climbs.
The eggs are usually more elongated than other hawks’ eggs, but they vary greatly in shape from ovate to short-rounded, elliptical, or elongate-ovate. The shell is fairly smooth and finely granulated. The ground color, which is often largely or wholly concealed, may be white. creamy white, pinkish white, “pale pinkish cinnamon”, “fawn color”, “light pinkish cinnamon”, or “vinaceous-cinnainon”. They are usually heavily blotched and spotted with dark rich browns, or bright reddish browns, “bone brown”, “liver brown”, “bay”, “chestnut”, “burnt sienna”, or various shades of “brownish drab.” Rarely they are marked with only the drabs, but often with both browns and drabs. The markings are sometimes concentrated at one end, or they form a ring, leaving much of the ground color exposed. Some are marked like duck hawks’ eggs, or caracaras’ eggs, and some like red-shouldered hawks’ eggs. Very rarely an egg is nearly immaculate. The brighter colors fade with age.
The measurements of 312 eggs in Mr. McMullen’s collection average 61 by 45.6 millimeters; the eggs showing the four extremes meastire 68.3 by 50.4, 55.2 by 45.5, and 60 by 41.7 millimeters. In the l3ancroft collection there is a longer egg, measuring 69.5 by 48, and a shorter egg, measuring 54.8 by 42.6 millimetera.
Young: Incubation, which is apparently performed solely by the female, lasts for about 28 days; the male feeds the female at the nest while she is incubating, but she sometimes leaves the nest for exercises or to fish for herself. Only one brood is raised in a season, but, if the eggs are taken, a second set will usually, though not always, be laid within three or four weeks. The earliest date on which I have found newly hatched young in Massachusetts is May 25; the latest date for unhatched eggs is June 18. The young remain in the nest about eight weeks. I have seen the young leave the nest as early as July 26, but most of them do not leave until the first week in August or later.
At first the young are very weak and helpless, lying prone in the nest and hardly able to lift up their heads. At this early stage, I suppose, they are fed on semidigested, regurgitated food, “fish chowder.” When ten days or two weeks old, they are able to sit up and move about some. At this age, they are fed on bits of raw fish, the male bringing in the fish, which is fed to the young by the female. Mr. Skinner, in his notes, describes a typical feeding scene very well, as follows:
I noted the male on the stub of a dead tree not far away, but with a fish. He bad cut off the head and disposed of the entrails. A moment after, two or three screams sounded and the male dropped down on the nest with the fish. Then the female stood up Quietly and the young birds immediately became interested. The father stood on the fish, that I judged had heen about a pound in weight, and tore It up, giving it bit by bit to the mother, and occasionally a tiny piece dlrectiy to a young bird. It was the mother, however, that did most of the feeding to the youngsters. After receiving the fish In not larger than half-Inch pieces, she ‘chewed’ them a bit, and then gave the nestilngs some after reducing the size somewhat. The proceedings were very orderly, the young birds remaining quietly in their places and not moving toward the fish only a few inches from them. Apparently, the trout was completely devoured; as I did not see any other disposal made of the bones and skin, I assumed that they were eaten along with the flesh.
Young ospreys are fed at infrequent intervals. I have read that they are fed only twice, or possibly three times, a day, before 8.30 a. in., around noon, and after 4.30 p. m. I have never watched a nest all day, but I have seen them fed at various times during both forenoon and afternoon. I believe that there are no regular feeding times but that feeding depends on the size and number of the young and the size of the fish caught. A large fish might serve for more than one meal. The feeding time also depends on when the adult succeeds in catching the fish, which is fed as soon as it is caught.
During the first few weeks, the young are only scantily covered with down, which matches their surroundings in the nest; the nests are usually in open situations, exposed to the full glare of the midsummer sun; they therefore suffer greatly from the heat, panting with open mouths and with moisture dripping from their tongues. The mother appreciates this and spends much time on hot days standing over them with half-open wings to shield them from the sun. After the young are well feathered, during the last few weeks of nest life, this protection is no longer needed, and the young are left alone in the nest for long periods.
Young ospreys are well camouflaged with concealing coloration during the downy stage, so well, indeed, that they might easily be overlooked by an aerial enemy; they are also past masters in the art of “freezing”, or feigning death. At a note of warning from their parents they lie flat in the nest with wings partly extended and neck stretched out on the floor of the nest, or hanging down among the outer sticks, and there they stay, absolutely motionless, until their mother gives them a note of assurance. They will even allow themselves to be handled without showing any signs of life, except for the motion of breathing or the winking of an eyelid. I have seen young ospreys hold this hiding pose for over an hour, even when partially fledged. Once, as I approached an osprey’s nest in a grove, the old birds made a great outcry; and, as I came near enough to see the nest, no young were visible. I withdrew and concealed myself. After the old birds had flown away and all was quiet, I saw three half-grown young stand up in the nest and watch for their mother’s return. She caine at last, saw me, and gave the warning cry. The young immediately dropped down out of sight; and although I remained in the vicinity for over an hour, the young never showed themselves again.
Very different behavior was noted in another nest in the same grove, which held two large young, fully fledged and nearly ready to fly. These youngsters evidently had nothing to fear, for they stood up in the nest constantly, craning their necks to watch my movements, in spite of the warning cries of both parents, who seemed greatly concerned. Probably the hiding pose is of importance only while the young are small and subject to attack by flesh-eating birds and is no longer necessary after they are large enough to defend themselves.
There is evidently considerable mortality among young ospreys; I have repeatedly noted that nests, occupied by brooding birds in May, were empty and deserted long before the time for the young to have flown. I once found a half-grown young lying on the ground. under a nest I was watching, with a badly crushed skull and one claw torn out. There had been a severe thunder storm the night before, which may have caused the young bird to fall out of the nest, and the skull may have been crushed by striking a stone wall directly under the tree.
Mr. Abbott (1911) gives a good account of the behavior of young ospreys, as follows:
Not until they are xveil feathered have I ever heard them emit anything approaching Osprey-like sounds; I have then observed them Imitate the cry of their parent overhead, in a charmingly babyish and amusing manner.
At this latter age they add to the death-feigning Instinct of the earlier period, a most interesting habit, which we may term ‘looking fierce.” If, as they lie fiat In the nest, they are approached too closely or touched, the first sign of life is a bristling of the feathers on the back. If the intrusion be continued they rise suddenly in the nest and turn toward one with ruffled feathers and glaring eyes, which, coupled with a desire to bite when opportunity offers, Is evidently calculated to scare the boldest of assailants. It does not take one long to discover, however, that this display of fierceness is mere show, and that even with Its formidable bill the young bird Is apparently incapable of Inflicting a painful wound. The attitudes assumed by young Ospreys during this “looking fierce” operation are often ludicrous in the extreme. They will spread or trail their wings, lower their heads in wicked fashion, raise their crests, and in general assume as formidable an aspect as possible. Sometimes they exhihit the power of extending the feathers of the throat and cheeks, forming a sort of mask. After standing for a few moments in this “terrifying’ attitude, the strength of the young bird begins to ebb and his muscles to relax; he will fall back on his ‘heels,” and his head will begin to droop forward. At this stage he will often be resting on “all fours,” so to speak, the “shoulders” of his wings acting as supports to the fore-part of his body. They gradually give way, however, and the bird’s bill comes closer and closer to the nest, until at last he is once more in his original prone and death-like position.
By the time the young are five or six weeks old they are strong enough to stand up and feed themselve~. The parent no longer tears up the food and feeds them, as described above, but drops the fish in the nest and flies away. The young then take turns feeding, standing over the fish, or on it, in a crouching attitude, with wings half spread and drooping. They are well behaved; I have never seen any evidence of quarreling; even with a small fish, they seem content to take turns. They are very neat in their sanitary habits; after a meal each bird backs up to the edge of the nest and squirts its excrement clear of the nest. As the wings develop faster than the young bird’s strength, they are allowed to droop, or are used as additional supports. About two weeks before the young are ready to fly, they begin their wing exercises, standing up and flapping the wings vigorously for several minutes at a time. After a week or so of this exercise, their wings are strong enough to lift them up a few feet above the nest, and then to attempt short, uncertain flights to nearby branches or to a perch above the nest. Finally, confidence in the power of its wings, or the example set by its parents, prompts the boldest of the young to make its first real flight away from the nest, a supreme moment in its life. With surprising ease it sails or flaps along, but it soon becomes tired and looks for a place to perch. Its attempts to alight on a treetop are awkward and uncertain; it has not learned to grasp a slender perch and finds it difficult to get its balance with much flapping of wings and wiggling of tail. It may be forced to alight on the ground to rest; I have often seen one do this; and it can rise from the ground quite easily. Such flights are short at first and the young always seem glad to return to the firm flat top of the nest, which will be their headquarters, bedroom, and dining room for several weeks yet.
Throughout the summer the young ospreys associate with their parents, playing with them in flying exercises, following them to the fishing grounds, and learning to fish for themselves. This latter they seem to do instinctively, as Mr. Forbush (1927) says: “They require no teaching, as individuals that have been brought up by hand and have never seen their parents catch fish, will begin fishing for themselves as soon as they have fully mastered the intricate problem of flight. At first they have very little success. I have seen a young bird plunge into a river seven times in succession without securing a fish, but the bird did not appear to be in the least discouraged, for it continued to follow the river and scan its waters in search of a victim.”
Plumages: The young osprey, when first hatched, is entirely unlike the young of any other hawk. It is not naked, as has been said, but is completely covered with very short, soft down, protectively colored. The color is mainly in shades of “pale pinkish buff” tinged with “cinnamon” on the crown; the lores, auriculars, and a large spot on the occiput are “bone brown”, and the sides of the neck are tinged with this color; the shoulders, back, wings, and rump, except for a wide buffy stripe dowii the center of the back, are “bone brown”, with “wood brown” tips; the entire under parts are “pale pinkish buff” and unmarked. This down is worn with but little change except fading until the plumage appears. There is no secondary down, as in young eagles and many hawks. A larger young bird, about a foot long, probably about three weeks old, shows some slight changes; the lores and auriculars are darker, brownish black, the latter nearly clear black; short feathers have appeared on the hind neck, “cinnamon-buff” to “pinkish cinnamon” in color; small feathers, similarly colored, are appearing on the wings and in the broad central, dorsal stripe, which has now faded to dull white; the dark areas, in which the down is still short and thick, are now “bister” in color; and the central belly is “drab.”
When about four weeks old, the plumage begins to appear, the black primaries showing first, then the black and white pattern of the head and the dusky, yellowish-tipped plumage of the mantle; when five weeks old the young bird begins to look like a real osprey. At this stage, in fresh juvenal plumage, the crown is buffy white, heavily streaked with brownish black; the hind neck is tinged with “cinnamon-buff”; the rest of the upper parts are “warm sepia” to “bister”, the feathers broadly tipped with “cream-buff”; the tail is broadly tipped with “cinnamon-buff”; the throat and fore breast are washed with “cinnamon-buff”, and the rest of the under parts are white.
This plumage is worn, with only slight and gradual changes, throughout the first year. The buff tips fade out to white and then wear away during the first winter. The head and neck become whiter. Some body molt begins late in fall or early in winter and is prolonged through spring and summer. The wings and tail may be molted in spring; but probably oftener in summer or fall. When the young bird is 18 months old, its plumage is practically adult.
Adults have a similar, prolonged molt, which may be in e4ridence during any month in the year.
The American osprey is supposed to have much less spotting on the breast than the European bird, but this character is none too well marked and none too constant in the series I have examined. The spotted breast, in the American bird, is said by some writers to be a character of the female, but in a series of 33 males and 22 females I find but little evidence of it. Among birds with white or nearly white breasts I find 13 males and 4 females; with lightly spotted breasts, there are 14 males and 9 females; and with heavily spotted breasts, I find 6 males and 9 females. A heavily spotted bird shows on each feather a large, concealed spot of “olive-brown” and a smaller, subterminal, triangular spot of “clay color” and “snuff brown”, with a dusky shaft streak; there are all gradations from the above to a bird with only the shaft streaks. In the European bird, the throat and upper breast are pale brown, sometimes tinged with rusty, forming a broad pectoral band. Very few American birds even approach this condition; these may be the younger birds, for I believe that the breast becomes whiter with advancing age.
Food: Fish is the almost exclusive food of the osprey, well named the fish hawk. The following species have been recorded in its food: Alewife or herring, bluefish, blowfish, bonito, bowfin, carp, catfish, eel, flounder, flying fish, goldfish, hornpout, menhaden, mullet, perch, pickerel, pike, salmon, shad, squiteague, sucker, sunfish, tomcod, trout, and whitefish; doubtless many others might be included. As the osprey is not a deep diver, it catches only such fish as swim on or near the surface, or in rather shallow water. Walter B. Savary writes to me of the following amusing incident: “This summer, while watching a fish hawk at his fishing, I saw him catch and lose four blowfish (Spkeroides nwzeulatus Nichols), the fish escaping each time by inflating itself until the hawk’s talons lost their hold. The bird was near at hand and I, through my field glasses, could see the fish as he blew himself up, and, when he fell, lie on the surface until he could deflate. The bird never got above ten feet from the water before the fish got loose.~~
Audubon (1840) says that the fish hawk catches flying fish while they are swimming near the surface but does not attempt to catch them in the air. I was much surprised one day to see an osprey flying over at short range with a small flounder in its talons; the hawk’s claws were embedded in the back of the fish, whose white belly and twitching tail were clearly seen. I marveled at the bird’s ability to dive deeply enough to capture a fish on the bottom, until I remembered that these small flounders often swim into shallow water; but I still marvel at the keen vision needed to locate a fish that matches the bottom so closely. The osprey is a clean sportsman and prefers to catch living fish, but it is not above picking up a dead fish if it is still fresh; but it is not a carrion feeder like the bald eagle and will not touch a tainted fish.
It has been stated repeatedly by good authorities, on apparently reliable evidence, that the osprey sometimes tackles a fish too big for it to lift, is unable to release its grip, is dragged under water, and is drowned. The evidence is too convincing and there is too much of it to dispute the fact, as the drowned osprey has been found on several occasions, sometimes still attached to the dead fish. Mr. Nicholson tells me that he has seen an osprey dive beneath the surface and never appear again. But it seems to me incredible that such a skillful fisherman would be foolish enough to tackle a fish big enough and strong enough to drag under water so powerful a bird with such a broad expanse of wing. It seems still more inconceivable that a bird that can so easily drop a fish in the air or at its nest cannot release its claws under water, even to save its life. There must be some other explanation for what has occurred; possibly the large, horny scales on the back of a sturgeon might entrap the claws of an osprey, if the bird were rash enough to tackle it. An osprey has been known to break its wing in diving (Fisher, 1893) I once caught one on the ground with a broken humerus.
Most of us have seen the osprey’s method of hunting, as it flies along at a moderate height above the water, scanning the surface for its Prey, flapping or sailing, or stopping to hover above a likely spot. Its keen eyes can sometimes locate a fish when flying at a height of 100 or 200 feet, but oftener it hunts at 30 or 100 feet above the water. When a fish is sighted, it plunges downward with half-closed wings enters the water with a splash, sending the spray flying, striking the water breast first, with wings extended upward, and seizes the fish in its strong talons; usually it does not go much below the surface, but sometimes it disappears for an instant or shows only the tips of its wings above the water. If successful, as it usually is, it rises heavily from the water with the fish in its talons, shakes the water from its plumage, and flies away to its nest or favorite perch. But not every attempt is successful, and not every fish seen is in a position that will insure a successful dive, so the osprey may pass on or even check its plunge in midair; but it keeps on trying until its persistence is rewarded. Mr. Skinner says of the ospreys in Yellowstone National Park: “Not only do they plunge into lakes and quiet stretches of streams, but I have also seen them hunt the swollen and raging Gardiner River in flood.”
The fish is invariably carried head first; probably it is usually caught that way, the approach from the rear being oftenest successful; but if caught otherwise it is turned about in the air. A small fish is carried in one claw, but a large one requires both, one claw in advance of the other. Just before the bird alights, the hinder claw is released to grasp the perch. I have seen an osprey bring to its nest a fish that must have weighed at least four pounds; I have read that it can carry one of 6, or even 8 pounds, though the latter seems unlikely.
Having secured its fish, the osprey flies with it to its nest, to some favorite perch, or to an unused nest, to eat it. It holds the fish down under one foot and is very deliberate about eating it; one that I watched waited half an hour before beginning to eat, and at the end of another half hour it had not finished; when I moved it flew away with much of the fish uneaten.
Another alighted with a fish on a half-built nest but did not start to eat it at once; when its mate came in and alighted beside it the first bird spread its wings and tail, crouching over the fish to guard it, until its mate flew away; this was before the eggs were laid and each bird had to fish for itself; eventually it flew away with the fish and half an hour later returned to the nest to eat it.
Mr. Abbott (1911) quotes Ernest H. Baynes, who had two young ospreys as pets, as follows:
They often began by picking out the eyes, perhaps because those organs were conspicuous and easily removed. They held their food in their claws, and usually before seizing any part of it, they would “finger” it, so to speak, with their bills, as though feeling for a good hold. They would tear off large pieces, jerk them backwards Into the throat and swallow them. They ate every part of the fish except the harder t)ones. Tough pieces were removed by a steady upward pull, and the ends of bones were twisted off with a pivotal movement such as a man would use to draw a nail with a pair of pIncers. Later, they ejected the bones and other indigestible particles in the form of pellets.
If the osprey ever takes any kind of food but fish it must be on very rare occasions; I can find very little positive evidence of it. It has been reported as eating young ducks, snakes, and frogs. Witherby (1924) says that it has been known to take chickens and that beetles have been found in its stomach. I once found a domestic pigeon in a nest, but. this was probably brought in with other miscellaneous material so often found in the nests. Dr. Robert C. Murphy told Mr. Abbott a remarkable story of an osprey that was killed by a woman while it was raiding her henyard; I quote it, in part as follows: “The woman told me that on the afternoon of the previous day, which had been rainy, she had been disturbed by a commotion among her chickens, and on going into her yard, had found the Hawk with its talons sunk in a hen, and flapping violently iii an attempt to fly off with its prey. She had killed the robber with a stick, and had freed the hen, which, however, died during the night. The Hawk which she gave me, was in a starved and emaciated condition, and was, of course, much bedraggled from lying out of doors in the rain.
Benjamin R. Warriner (1934) saw an osprey catch a turtle, of which he says: “When he rose from the water he carried a black object which I could not at first identify. Then I could see: a turtle some six or seven inches across. The Osprey fought desperately to hold his victim, but of course the turtle’s bony covering prevented the bird’s claws from penetrating below the surface. Suddenly he lost his hold and the turtle came down hard upon a big stump, and bounced off into the water.”
Behavior: The flight of the osprey is powerful and well sustained, swift and dashing at times, but oftener slow and heavy. It soars at times on motionless wings but ordinarily proceeds with deliberate flappings. In ordinary traveling flight the wing is somewhat flexed at the wrist joint; even when the bird is soaring the wings are not held so straight out as they are in the Buteos. This curvature of wing makes the osprey recognizable often at a long distance. When hovering over a fish, the wings are flapped rapidly, but the body is not held in the vertical position assumed by the kingfisher. In flight the feet are extended under the tail.
The behavior of ospreys about their nests is characteristic, quite uniform, and quite different from that of any other bird of prey. As soon as a stranger is seen approaching, the sitting bird, who is always on the lookout for trouble, rises up and begins her musical, whistling cackle; as the man draws near, her notes become shriller, increasing to loud, ear-piercing screams, intercepted by the short, sharp, impulsive ick, ick, ick notes, on a lower key and more metallic. She soon leaves the nest and circles about, screaming lustily; she is then joined by her mate and perhaps one or two of her neighbors. If the man climbs the tree, he must expect to be attacked, or at least threatened, although this does not always happen. The method of attack is to make vicious swoops at the intruder, but seldom striking him.
I have frequently been attacked and even struck on the head and shoulders, but have never even been scratched; a rush of wings, as the bird swerves uncomfortably close, is the usual experience. Many birds are content to fly about and scream at a safe distance, but they do not fly away and desert their nests, as other hawks do. Ospreys that nest near houses seem to recognize harmless friends and pay no attention to familiar human beings; but with strangers their behavior is very different.
Only once have I ever found an osprey “asleep at the switch” in daylight. We visited an old nest 60 feet up in a tall pine in some woods but saw no birds about it and concluded that it was unoccupied. After a while we heard an osprey whistling in the vicinity; we returned to the big pine and rapped it; much to our Surprise the bird flew off the nest. That was the only time I have ever had to rap a tree to flush an osprey, except at night when they probably sleep on the nest. I believe that both birds spend the night in the nest tree; we have several times in complete darkness flushed both birds while climbing the tree.
In spite of their frequent plunges into the water, ospreys like to bathe occasionally. Pearson, Brimley, and Brimley (1919) say: “A curious habit of the Osprey is that of ‘foot-washing.’ From flapping in wide circles over the lake a bird may be seen suddenly to half close its wings and glide toward the water in a long, gentle sweep. When almost touching the surface, the feet are dropped to the full extent of the long legs and a horizontal flight of fifteen or twenty yards follows, while the feet drag in the water. The reason for this action is doubtless to cleanse the toes and claws of the fish-slime that must necessarily accumulate on them.”
L. MeCormick-Goodhart (1932) watched an osprey bathing on a sandy point and writes:
The bird stands in about six inches of water, and bathes in the same manner as other birds, by ducking himself under and then vigorously flapping his wings. On May 15, 1932, however, I witnessed what appeared to be a new method of bathing. When I observed the bird this time (through a 16x binocular) it was flying towards me, about six feet above the surface. It was observed suddenly to descend into the water, and then adopt a sort of vertical American-eagle attitude while flapping Its wings two or three times before rising again. It then again flew along the water, keeping the same general direction, and repeated this form of immersIon some five times, finally rising to a normal flight.
I once saw a different method of bathing. While driving past a small pond we saw an osprey perched on a low stake On the edge of the pond, and we stopped to watch him. He rose, circled around the pond once or twice, and then dove into the water head first, going entirely below the surface; he rose to the surface almost immediately and flopped along it for a few yards, flapping his wings vigorously and ducking his head under water occasionally. He then rose, shook the water from his plumage, circled the pond again, and flew back to his perch. This performance was repeated three or four times at intervals of only a few minutes. We did not see him preen his plumage. He was evidently not fishing but seemed to be enjoying his bath.
In its relations with other species the osprey is a peaceful, gentle, and harmless neighbor. Only such species as might harm its eggs or young are attacked or driven away. If unmolested it attends strictly to its own business, in which it is very industrious. A very large proportion of the osprey’s nests that I have seen have contained one or more nests of the English sparrow or the starling among the lower sticks. Mr. Abbott (1911) says that “Purple (irackles especially, commonly build in convenient niches among the sticks even of the ground nests. Being naturally gregarious, they will congregate to the number of six or seven pairs in one Osprey’s nest. Ospreys are recorded to have admitted House Wrens and even Night Herons as basement tenants. On the beaches, Meadow Mice have found the nests to be convenient mounds under which to construct their multifarious run-ways.”
Mr. Abbott (1911) found the ospreys nesting in the night-heron. colony on Gardiners Island, apparently peacefully. But Mr. Allen (1892) gives a different impression of the behavior of the ospreys toward the herons, which the former may have regarded as enemies; he writes:
In the swamp near the Fish Hawks’ nests was a colony of Night Herons, nesting in the smaller trees near the swamp. Almost daily a flock of Crows from Connecticut were accustomed to rob this heronry, covering the ground with the shells of the eggs they had eaten, and occasionally treating a few Fish Hawks’ nests in the same way. The Fish Hawks seemed to unjustly accuse the Herons of this robbery, as the Herons were constantly persecuted by the Hawks. Whenever a Heron appeared he was instantly set upon by one or more of them, and the Herons would seek safety in the thick underbrush where the Hawks could not follow them. Herons were killed, however, almost daily by the Hmvks.
Enemies: In addition to the thoughtless gunner, who shoots ~very large bird that he can, and the greedy egg collector, who takes all the eggs he can get for exchange, the osprey has a number of natural enemies, most of which are more annoying than harmful. The bald eagle is undoubtedly its worst enemy. Its well-known habit of attacking the osprey, to rob it of its well-earned prey, has been described in my account of the southern bald eagle and many times by other writers, so I shall not repeat it here. In Florida, where the ospreys often nest well inland, the eagles lie in xvait for them as they fly from their fishing grounds back to their nests. The osprey seldom escapes from these attacks, but a clever attempt at dodging, when pursued by two eagles, is thus described by Henry G. Vennor (1876) On first hearing the shrill screams of its pursuers, the poor bird made desperate efforts by straight flight to reach the drowned woud-lands in which its nest and young were loceted; hut long before it reached these its course was intercepted by one of the Eagles, while the other made repeated and fierce stoops at It from above. The Fish Hawk, however, still held on firmly to its prize, and made repeated attempts to baffle the onsets of the Eagle, in many of which it was successful. Before long both birds had risen to a great height: the one alternatingly surmounting the other; hut xve could still detect every now and then the gleam of the fish in the sunlight. Suddenly, the Fish Hawk was seen to descend with great velocity towards the water, and we thought the poor bird had been struck, and perhaps mortally wounded. It, however, as suddenly checked its downward course, and tile Eagle which had as quickly followed it, shot past and far below it; and now once more the pursued bird made straight for Its nesting site, hut again was intercepted by the other Eagle, which made desperate by the protractedness of the chase, struck fiercely at it with piercing screams. Baffled on every side, wearied and blinded with the repeated buffettings of the Eagles, the Fish Hawk, with a scream of rage, let go its prize, which fell head long towards the water.
The osprey will drive away an eagle or any other bird of prey from its nest and young, but I once saw one attack an eagle several miles away from any nest and long after its young were on the wing. Several times it swooped down, as both birds were circling high in the air, almost striking the eagle; the latter turned on its back each time and presented its talons, which sent the osprey scaling off in a hurry. Edward Fuller (1891), quoting “a gentleman who witnessed a scene 6f this kind”, describes a joint attack on an eagle by a colony of ospreys, as follows:
They seemed to have formed a sort of colony for mutual protection, and the moment their foe, the Eagle, made his appearance among them, the cry of alarm ivas raised, and the vigilant colonists, hurrying from all quarters, attacked the robber without hesitation, and always succeeded in driving him away.
There was always a desperate battle first before the savage monarch could he routed, and I have seen them gathered about him in such numbers, whirling and tumbling amidst a chaos of floating feathers through tile air, that it was Impossible for a time to distinguish which was the Eagle, until having got enough of it against such fearful odds, he would fain turn tail, and with most undignified acceleration of flight would dart toward the covert of the heavy forest to hide his baffled royalty, and shake off his pertinacious foes amidst the boughs.
Dr. Theodore Gill (1901) quotes an interesting account of the persecution of ospreys by man-o’-war-birds, as observed by I. Lancaster in southern Florida. The ospreys seemed to be in mortal terror of these pirates, who not only made them drop their fish by merely threatening an attack, but sent them, screaming, back to the land in hurried flight. The reason for the ospreys’ dread of these black-winged rascals is told in his thrilling account of an attack, by a number of mnn-o’-war-birds, on an osprey that they had robbed. The poor bird was chased about in the air and all his frantic atiempts to escape were headed off, until he became so exhausted that lie dropped into the water. Even there his tormentors continued their attack forcing him under the water, until he was finally killed.
Crows are always on the lookout for unguarded eggs and have been known to puncture and suck ospreys’ eggs; consequently the ospreys always drive them away from their nesting grounds. Owen Durfee describes such an instance in his notes; he was “interested, in watching a fish hawk flying along near its nest, to see a crow fly up and chase the fish hawk, diving down on its back. Finally the fish hawk grew tired of this and made a savage swoop at the crow. Apparently the crow did not heed this warning, for he once more rose and dove at the fish hawk. Then the latter bird really made things lively for a few moments for the crow, attaeking him from all directions, and finally driving him off into the woods, but never appearing to really strike him, the crow dodging in fine shape.”
Large herons have been suspected of eating the very small young, and hence are potential enemies. Mr. Nicholson tells me that “the osprey is extremely pugnacious towards both the black and the turkey vultures, which may venture near its nest, and drives them away with great fierceness and display of anger. Possibly the blacks have been guilty of going to the nests and stealing choice morsels or killing the young. I twice found great holes in osprey eggs that were drained of their contents, which I took to be the work of fish crows.”
Almost any small bird will drive away from the vicinity of its nest any predatory bird. The kingbird is one of the most aggressive defenders of its home territory and drives the osprey ignominiously away. Blackbirds, grackles, and starlings attack the osprey singly or mob him in flocks, swarming around him until he is glad to beat a retreat. I have seen even a barn swallow chasing one. Unless pestered with overwhelming numbers, the osprey pays but little heed to these small tormentors. Mr. Abbott (1911) says that on Gardiners Island the ospreys that have their nests near a colony of common terns “are being continually harried ‘by the Terns. I have seen an Osprey driven from her nest by a Tern three or four times within a quarter of an hour.”
Voice: The osprey is a noisy bird about its nest, and its vocal efforts are most interesting and quite characteristic. One reason for its popularity among farmers is that it is a good “watch dog”, always alert and sure to give the alarm with its loud cries as soon as a stranger approaches. The alarm note begins with a loud, rich, musical whistle, cheeap, cheeap, many times repeated; as excitement increases, this is lengthened into a much shriller angry scream of great intensity, interrupted with, or ending in, a sharp, metallic ick, ick, ick, a harsh rasping note on a lower key. When undisturbed it has a weak note, which reminds me of the “cheeping” note of a young chicken. There is also a soft note of greeting, as the bird returns to its mate or young, sounding like chirrup. Mr. Abbott (1911) has described the alarm notes very well, as follows “The commonest note is a shrill whistle, with a rising inflection: Whew, whew, whew, whew, whew, whew, whew. This is the sound usually heard during migration; and when the bird is only slightly alarmed. When she becomes thoroughly aroused, it will be: Chick, chick, chick, cheek, cheek, c/i-cheek, c/i-cheek, c/iee’reek, chezeck, chezeek, gradually increasing to a frenzy of excitement at th.e last. Another cry sounds like: Tseep, t8ecp, tseep-whick, which, whick-ick-ick-ek-ek, dying away in a mere hiccough. And there are endless variations quite incapable of syllabification.”
Dr. Frank M. Chapman (1908) calls the food call “a high, rapidly uttered tweet-tweet-tweet”; probably it is also a note of assurance to the young that danger has passed. William Brewster (1925) says that “in calm summer weather their musical whistled calls, not unlike those of the Purple Martin, but much louder, fall pleasantly on the ear at frequent intervals, coming from far and near over the shining Lake.” Dr. Winsor M. Tyler contributes the following impressions:
The note most frequently heard from the osprey, as it moves northward In migration, pausing to fish in the lakes, ponds, and larger rivers which it meets on its journey, is a rather shrill squeal: not full-voiced, but with a slight hissing quality. The note sounds petulant, and calls to niind a smaller bird than this great hawk with its fine spread of wings.
About its nest the osprey is a noisy bird. It flies off when approached, giving a long series of notes, somewhat whistled in quality, but often harsh and rasping. These notes are uttered with the beak open throughout the series and suggest the cry of the yellowlegs. They may be written he-ku-ku, or 1w-to-he, and are delivered at the rate of the flickers shouted tcik-teik-w-ik, and nearly on the same pitch, although the voice may slide upward a little way, or, at the end, downward to a considerable degree. A modilication of this note, shortened to two rapid syllables, the first sharply accented, k-e-oo, bears a decided resemblance to the call of the evening grosheak.
The bird on its breeding ground has also a dull chatter and the squeal mentioned ahove, the inflection often varying, the pitch sometimes sweeping upward, and sometimes dropping a little. All these notes give an impression of querulousness rather than of hostility, and seem inadequate to express the emotions of so large a bird.
During the autumnal migration, and during winter, as I have seen the osprey in Florida, it is for the most part silent.
The bend in the wing and the manner of flight, described above, will ~rve to distinguish the osprey from other hawks at a great distance. The white breast can be seen almost as far away, and the distinctive head markings are a good field mark at short range.
Fall: Mr. Hathaway (1905), referring to southern New England, says: “The return movement to their southern habitat commences in August, and probably their place is taken by birds from breeding places in the more northern states which pass on, or linger as the weather may be favorable or not, as late as October or early November. A large majority of the birds which are shot in the fall by hunters are young birds of the year, leaving us to conclude that the adults are the first to depart, while the young follow as they grow stronger and are able to stand the long flight to warmer climes.”
Dr. Charles XV. Townsend (1905) records the heaviest flight through Essex County, Mass., during the last week in September and says that it “generally precedes a heavy flight of ducks.” Mr. Skinner’s dates for Yellowstone National Park are about the same; his latest date is October 7.
Throughout the southern portions of its range the osprey is permanently resident; its numbers are greatly increased in winter with migrants from farther north.
Range: As a species the osprey is nearly cosmopolitan, and the form of the Western Hemisphere (carolinensis) ranges north to Alaska and Labrador (accidental in Greenland) and south casually to Paraguay, Argentina, and Chile.
A tropical form, Pandion 1ialia~tus ridgwayi Maynard, has been described. it is resident in the Bahama Islands, the coasts of Yucatan, and in British Honduras.
Breeding range: The breeding range extends north to Alaska (Kowak Delta, Fort Yukon, and Kandik River); Mackenzie (Fort Rae and Bear Lake River) ; northern Alberta (Poplar Point); northern Saskatchewan (lie a la Crosse, Knee Lake, and Churchill River); northern Manitoba (Grass River, probably Churchill, and probably York Factory) ; northern Ontario (Poplar River and Moose Factory) Quebec (Lake Mistassini, Godhout, and Anticosti Island) ; and Labrador (Northwest River and White Bear River). East to Labrador (White Bear River and XVolf Bay) ; Newfoundland (St. George Bay); Nova Scotia (Sydney, Antigonish, and Halifax); Maine (North Haven and Jericho Bay) ; southeastern New Hampshire (Manchestei.) ; Massachusetts (Swansea, Wareham, and Falmouth); New York (Plum Island and Gardiners Island) ; New Jersey (Red Bank, Penusyule, and Cape May) ; Virginia (Chincoteague Island, Hog Island, and Newport News); North Carolina (Orton Lake); South Carolina (Charleston); Georgia (Savannah, Blackbeard Island, Cumberland Island, and St. Marys) ; and Florida (St. Augustine, New Smyrna, Wekiva River, Lake Jstokpoga, and Florida Keys.) South to Florida (Florida Keys. Bocagrande, Marquesas Keys, St. Marks, Alaqua Bayou, and Pensacola) ; Alabama (Perdido Bay. Orange Beach, and Spring Hill); Louisiana (New Orleans and Bayou Sara); probably rarely Texas (Refugio County and Corpus Christi); and Lower California (Tres Marias Islands and Cape San Lucas). West to Lower California (Cape San Lucas, Santa Margarita Island, Natividad Island, Cerros Island, San Benito Island, San Geronimo Island, San Martin Island. and Todos Santos Island) ; California (San Diego, San Clemente Island, San Nicolas Island, Clearlake, Garberville, Humboldt Bay, and Requa); Oregon (Ochoco River); Washington (Bellinghain and Simiahoo); British Columbia (Chilliwack, Court.day, Friendly Cove, probably Massett, and Atlin); and Alaska (Sitka, Tocotna, North Fork, Nulato, and Kowak Delta). Winter range: In winter the osprey is found north to California (Farallon Islands); Arizona (Salt River); Texas (Eagle Pass and Rockport) ; Louisiana (State Game Preserve and New Orleans) Mississippi (Natchez) ; and Florida (St. Marks and Fruit Cove). East to Florida (Fruit Cove, Daytona, Pence de Leon Inlet., Orlando, Royal Palm Hammock, and Alligator Lake) ; Haiti (Seven Brothers Islands and Monte Christi); Puerto Rico (Mameycs and Vieques Island) ; the Lesser Antilles (St. Vincent, the Grenadines, Carriacou, Grenada, and Trinidad); probably eastern Venezuela (Waini River and Barima River); probably British Guiana (Abary River) ; western Brazil (Caicara) ; and Paraguay (Rio Negro). South to Paraguay (Rio Negro); rarely Argentina (Tucuman); and rarely Chile (Reloncavi Bay). West to rarely Chile (Reloncavi Bay); northwestern Peru (Santa Luzia); Ecuador (Chone); Colombia (Bonda); Panama (Farfan); Costa Rica (Guacimo); Nicaragua (Escondido River); Oaxaca (Ventosa Bay); Federal District of Mexico (Lake Chalco); Lower California (Natividad Island and Cerros Island); and California (San Diego, Santa Cruz Island, and Farallon Islands). Ridgway (1874, p. 324) reported the osprey as resident at Mount Carmel, Ill., but it is believed that was an error. A specimen reported as seen at Morristown, N. J., on December 25, 1918, probably was misidentified. Spring migra.tion: Early dates of arrival in the spring are: Georgia: Savannah, February 24; St. Marys, February 24; Darien, March 10; and Athens, April 9. South Carolina: Charleston, February 14; Frogmore, March 3; and Columbia, April 13. North Carolina: Raleigh, March 5; and Walke, March 21. Virginia: Newport News, February 17; Hicks Wharf, March 15; and Camp Eustis, March 19. District of Columbia: Washington, March 19. Maryland: Baltimore, March 11 Rock Hall, March 14; Chestertown, March 16; and Cambridge, March 17. Pennsylvania: Wayne, February 10; Germantown, February 18; Westtown, March 17; and Lancaster, March 30. New Jersey: Cape May, March la; Mount Bethel, March 14; New Brunswick, March 19; and Asbury Park, March 25. New York: Shelter Island, March 18; Gardiners Island, March 20; and Rochester, March 31. Connecticut: New Haven, March 24; Portland, March 25; and East Hartford, April 1. Massachusetts: Taunton, March 16; Dartmouth, March 29; and Boston, March 30. Vermont: St. Johnsbury, March 19; Wells River, March 28; and Rutland, April 1~. New Hampshire: Concord, April 8; Peterborough, April 10; and Durham, April 13. Maine: Orono, March 27; Eagle Island, April 5; and Pittsfield, April 6. Quebec: Montreal, April 10; East Sherbrooke, April 14; and Quebec City, April 29. New Brunswick: Scotch Lake, April 8; St. John, April 11; and St. Andrews, April 14. Nova Scotia: Bridgetown, April 18; and Pictou, April 12. Prince Edward Island: Alberton, April 24; and North River, May 1. Newfoundland: Raleigh, May 10. Arkansas: Pike County, April 2; and Amity, April 11. Tennessee: Nashville, April 14. Kentucky: Lexington, April 17; and Pine Mountain, April 28. Missouri: Warrensburg, April 8; Auburn, April 20; and St. Louis, April 23. Illinois: Shawneetown, April 1; Alton, April 4; and Elgin, April 12. Indiana: Terre Haute, March 22; Indianapolis, March 25; and Rockville, April 1 (there also is an unusually large number of observations for Indiana early in March, and some as early as February 20, Bloomington, and February 11, La Fontaine). Ohio: Columbus, March 28; Barnesville, April 1; Youngstown, April 3; and Oberlin, April 5. Michigan: Ann Arbor, March 10; Sault Ste. Marie, March 27; and Pontiac, April 8. Ontario: Ottawa, April 10; London, April 11; and Toronto, April 16. Iowa: La Porte City, March 15; Sioux City, March 19; and Davenport, March 28. Wisconsin: Milwaukee, March 10; Foxlake, March 21; and Madison, April 1. Minnesota: Fort Snelling, April 11; Elk River, April 13: and Lanesboro, April 15. Kansas: Lawrence, April 14; and Ellis, April 10. Nebraska: Neligh, April 1; and Lincoln, April 23. South Dakota: MeCook Lake, April 19. North Dakota: Jamestown, April 23; and Snyder Lake, April 24. Manitoba: Margaret, April 21; and Aweme. May 2. Saskatchewan: Indian Head, April 8; and Crooked Lake, May 3. Mackenzie: Fort Resolution, May 10. Colorado-Loveland, April 8; Durango, April 10; and Denver, April 25. Wyoming: Y~llowst one National Park, April 9; Laramie, April 23; and Jackson Hole, May 2. Idaho: Minidoka Bird Refuge, March 1; and Rathdrum, April 1. Montana: Columbia Falls, April 16; and Bitterroot Valley, April 17. Alberta: Pine Lake, April 26; and Banif, April 29. Oregon: Mercer, April 1 (may be a rare and local resident). Washington: Cashmere, March 27; Puyallup, March 31; Chelan, April 17; and Tacoma, April 18. British Columbia: Okanagan Landing, March 27; Mirror Lake, April 2; Courtenay, April 3; Chilliwack, April 6; Hastings, April 10; and Masset, April 24. Alaska: Nulato, May 8; and Kowak River, June 3.
Fall migration: Late dates of fall departure are: Alaska: Bethel, September 7; and Kowak River, September 20. British Columbia: Chilliwack, October 11; Mirror Lake, October 20; and Okanagan Landing, October 30. Washington: Yakima, November 15. Al. berta: Belvedere. September 17. Montana: Rockhill, October 2.Idaho: Priest River, October 6. Wyoming: Yellowstone National Park, October 4. Colorado: Yuma, September 29. Mackenzie: Great Slave Lake, September 20; and Fort Good Hope, October 2. Saskatchewan: Indian Head, September 10. Manitoba: Treesbank, October 3; and Aweme, October 12. South Dakota: Grand River Agency, October 7; and Vermillion, October 15. Nebraska: Badger, October 1; and Jackson Lake, October 9. Kansas: Lawrence, October 10. Oklahoma: Norman. November 25. Minnesota: Lanesboro, October 21. Wisconsin: Ellihorn, October 1; Racine, October 3; and Burlington, Novcmber 10. lowa: Osage, October 13; Davenport, November 1; and Keokuk, November 12. Ontario: Point Pelee, October 14; Ottawa, October 17; and Port Dover, October 19. Michigan: Sault Ste. Marie, October 19; South Lyon, October 21; and Detroit, November 18. Ohio: Upper Sandusky, October 12; Austinburg, October 29; and Columbus, October 30. Indiana: New Harmony, October 28 (once observed on December 6); and Crawfordsyule, November 21. Illinois: Lake Forest, September 26; Horseshoe Lake, September 29; and Springfield, October 10. Missouri: Marionville, September 13; Monteer, September 22; and Iberia. October 15. Kentucky: Bardstown. October 18. Tennessee: Nashville, October 7. Prince Edward Island: Alberton, September 25. Nova Scotia: Sable Island, September 30; and Pictou, October 13. New Brunswick: Scotch Lake, November 7. Quebec: Montreal, September 17; and Quebec City, September 26. Maine: Phillips, October 9; Lewiston, October 13; Avon, October 26; and Owls Head Light Station, October 28. New Hampshire: Concord, September 21. Vermont: Woodstock, October 19; and Wells River, November 8. Massachusetts: Harvard, October 18; Danvers, October 24; Marthas Vineyard, October 30; and Boston, November 8. Connecticut: Hadlyme, October 28; Meriden, October 29; and Danbury, November 13. New York, Ithaca, October 25; Howard, November 12; and Fire Island Light, November 25. New Jersey: Elizabeth, October 13; Sandy Hook, October 16; Hackettst.own, November 2; and Morristown, December 25. Pennsylvania: Renovo, November 7; Doylestown, November 9; Berwyn, November 13; and York, December 15. Maryland: Chestertown, October 23; and Baltimore. November 8. District of Columbia: Washington, November 30. Virginia: Backbay, November 20. North Carolina: Raleigh, October 5; and Knotts Island, November 17. South Carolina: Charleston, December 6. Georgia: Atlanta, October 20.
More definite information concerning the fall migration of ospreys on the Atlantic coast is afforded by a consideration of the available banding data. Five birds banded as fledglings at Avalon, N. J., one in June and four in August, were all recovered in September and
October, four in the former month and one in the latter. Three of the September recoveries were in West Virginia and one was in North Carolina. The October bird was taken at McIntyre, Fla. Another, banded at Gardiners Island, N. Y., in July, was caught in a steel trap the following September at Hancock, Md. one banded in July at Milford, Del., was taken at Sitlington, Va., in September; and another banded in July at Gardiners Island, N. Y., was recaptured at Shell, S. C., also in September, which is clearly the principal month of the southward movement on the Atlantic coast. While the West Virginia records scem to indicate a migration route in the interior, H. H. Bailey (1913, p. 281) has recorded one that came on board a vessel about 100 miles east of Cape Hatteras, N. C., on October 16, 1911. The banding files contain the records of two more recoveries in this same general area. One, banded at Orient, Long Island, N. Y., on June 30, 1928, was retaken 60 miles offshore on September 20, 1928; the other, also bai~cled at Orient on July 23, 1933, was shot 73 miles at sea off Cape Hatteras on October 9, 1933.
The distance traveled in migration by ospreys is indicated by two banding records. One, handed at Slaughter Beach, Del., on April 25, 1932, was retaken on the Milk River, Jamaica, British West Indies, on March 10, 1933; while the other, banded at the same place on April 26, 1934, was recovered at El Mojan-Estado, Ziilia, Venezuela. on June 28, 1935.
Casual records: According to Macoun (1903, p. 261) “a. single specimen was obtained at Godhaven, Greenland, by Mr. E. Whymper and sent to the Museum at Copenhagen.”
Egg dates: Quebec.: 35 records, May 24 to June 28; 18 records, May 28 to June 8.
New York and New England: 48 records, April 25 to June 18; 24 records, May 6 to 18.
Delaware and New Jersey: 513 records, April 24 to June 16; 251 records, May 3 to 25.
Maryland and Virginia: 90 records, March 10 to May 30; 45 records, April 29 to May 8.
Florida: 19 records, December 4 to April 28; 10 records, March 13 to April 10.
California: 15 records, March 14 to May 30; 8 records. April 2 to May 3.
Lower California and Mexico: 29 records, January 22 to April 16; 15 records, February 20 to April 8.