Prothonotary Warbler

The Prothonotary Warbler has greenish upperparts, blue-gray wings, and a bright yellow head, breast, and belly, with white undertail coverts.

The sexes are similar though males can have brighter yellow heads.  Length: 5 in.  Wingspan: 9 in.

Photograph © Greg Lavaty.

The sexes are similar, though females can have somewhat greenish heads.

None.

Immatures are similar to adults, but with greener heads.

Prothonotary Warblers inhabit river bottom hardwoods, cypress swamps, and lakes or ponds bordered by trees.

Prothonotary Warblers eat insects and snails.

Photograph © Greg Lavaty.

Prothonotary Warblers forage by gleaning prey from low foliage in trees and shrubs.

Prothonotary Warblers breed across much of the eastern U.S. They winter from Mexico south to South America. The population has declined in recent decades.

More information:

Bent Life History

Visit the Bent Life History for extensive additional information on the Prothonotary Warbler.

The Prothonotary Warbler’s name comes from the bright yellow color of the robes of a Catholic official known as a protonotarius.

Prothonotary Warblers readily accept nest boxes, and even use unusual nest sites such as old coffee cans and mailboxes.

The song is a series of clear, rising whistles. A short, high-pitched flight call is also given.

The Prothonotary Warbler’s nest is a cup of moss, leaves, and twigs and is lined with finer materials. It is placed in a natural cavity, old woodpecker cavity, or nest box.

Number: Usually lay 5 eggs.
Color: Whitish with darker markings.

Incubation and fledging:
The young hatch at about 12-14 days and fledge at about 10-11 days, though remaining dependent on the adults for some time.

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 Prothonotary Warbler – the common name and sub-species reflect the nomenclature in use at the time the description was written.

I do not like the above name for the golden swamp warbler. The scientific name Protonotaria, and evidently the common name, were apparently both derived from the Latin protonotarius, meaning first notary or scribe. I sympathize with Bagg and Eliot (1937), who exclaimed:

What a name to saddle on the Golden Swamp-bird! Wrongly compounded In the first place, wrongly spelled, wrongly pronounced! We understand that Protonotarius is the title of papal officials whose robes are bright yellow, but why say “First Notary” in mixed Greek and Latin, instead of Primonotarius? Proto Is Greek for first, as in prototype. Why and when did It come to be misspelled Protho? Roth Wilson and Audubon wrote Protonotary Warbler, a name seemingly first given to the bird by Louisiana Creoles. Both etymology and sense call for stress on the third syllable, yet one most often hears the stress laid on the second. Here, certainly, is a bothersome name fit only to be eschewed!

The scientific name cannot be changed under the rules of nomenclature, but a change in the common name would seem desirable. However, the name does not make the bird or detract from its charm and beauty. It will still continue to thrill with delight the wanderer in its swampy haunts.

The center of abundance of the prothonotary warbler as a breeding bird in this country is in the valleys of the Mississippi River and its tributaries, notably the Ohio, the Wabash, and the Illinois Rivers. Its summer range extends eastward into Indiana and Ohio, northward into southern Ontario, Wisconsin, Michigan, and Minnesota, and westward into Iowa, Nebraska, Kansas, Oklahoma, and eastern Texas: wherever it can find suitable breeding grounds.

It also breeds in the Atlantic Coast States from Virginia to Florida. It is essentially a bird of the damp and swampy river bottoms and low-lying woods, which are flooded at times and in which woodland pools have been left by the receding water. Perhaps this warbler abounds more than anywhere else in the valley of the lower Wabash, where William Brewster (1878) found it to be: one of the most abundant and characteristic species. Along the shores of the rivers and creeks generally, wherever the black willow (Salix niger) grew, a few pairs were sure to be found. Among the button-bushes (Cephalanthus occidentalis) that fringed the margin of the peculiar long narrow ponds scattered at frequent intervals over the heavily timbered bottoms of the Wabash and White Rivers, they also occurred more or less numerously. Potoka Creek, a winding, sluggish stream, thickly fringed with willows, was also a favorite resort; but the grand rendezvous of the species seemed to he about the shores of certain secluded ponds lying in what is known as the Little Cypress Swamp. Here they congregated in astonishing numbers, and early in May were breeding almost in colonies. In the region above indicated two things were found to be essential to their presence, namely, an abundance of willows and the Immediate proximity of water. * * * So marked was this preference, that the song of the male heard from the woods indicated to us as surely the proximity of some river, pond, or flooded swamp, as did the croaking of frogs or the peep of the Hylas.

Dr. Chapman (1907) writes of this bird in its haunts:

The charm of its haunts and the beauty of Its plumage combine to render the Prothonotary Warbler among the most attractive members of the family. I clearly recall my own first meeting with it In the Suwanee River region of Florida. Quietly paddling my canoe along one of the many enchanting, and, I was then quite willing to believe, enchanted streams which flowed through the forests into the main river, this glowing hit of bird-life gleamed like a torch in the night. No neck-straining examination with opera-glass pointed to the treetops, was required to determine his Identity, as, flitting from bush to hush along the river’s bank, his golden plumes were displayed as though for my special benefit.

Dr. Lawrence H. Walkinshaw (1938) says that the golden swamp warbler “nests rather abundantly along southwestern-Michigan rivers. * * * Winding streams, bordered densely with oak, maple, ash, and elm, shallow ponds with groups of protrudnig willows and flooded, heavily shaded bottom-lands are favorite nesting habitats for the Prothonotary Warbler (Pro tonotaria citrea). Stich habitats occur along the banks of the Kalamazoo River and its tributary the Battle Creek River in Calhoun County, Michigan.”

Territory: The males arrive on the breeding grounds a few days or a week before the females come and immediately try to establish their territories, select the nesting sites, and even build nests. Dr. ~Tafldnshaw (1941) writes:

The Prothonotary Warbler is a very strongly territorial species. When a male takes possession of a certain area he continually drives off all opponents if he Is able. At certain areas in Michigan I have watched these birds battle Internuttently for two or three days, usually for the same bird house, one male finally taking possession. In addition I have observed them to drive off House Wrens (Trogiodyte~ aedon), Black-capped Chickadees (Penth~eates atricapillw8) and Yellow Warbiers (Dendroica aestiva). * ï * Tile male Prothonotary Warbler selects the territory, selecting the nesting site before he becomes mated for the first nest, but thereafter both birds inspect the new nest sites.

On observations made near Knoxville, Tenn., Henry Meyer and Ruth Reed Nevius (1943) found that: three males established territories. Male I arrived April 14. By the next day he was singing on an area 550 feet long and for the most part not more than 200 feet wide. It included three kinds of habitats: (a) a grassy terrace on which several nesting boxes were located, (b) river banks densely covered with small trees and bushes, and Cc) a small open orchard which constituted the connecting link between the terrace and the river bank. Male II arrived on April 18 and occupied a narrow territory along a brook confined by wooded slopes and which contained two lotus ponds. The area was about 400 feet long and 100 feet wide. A nesting box was on a stake above one of the ponds. Male III appeared May 5 in the terraced area being claimed by Male I. During the day, the 2 males sang energetically and flew often only a few inches apart. Male I maintained his territory and Male III disappeared.

There were a number of nesting boxes on the area that the males investigated, carrying nesting material into some of them while they were waiting for the females to arrive. The mate of the first male came on April 20, and: on this day this pair communicated by their full call-note. Twice the male was seen pursuing tile female rapidly In a small semi-circle and pausing, called a soft, full note which was later heard only when the two sexes were together. The mate of Male H came April 22, four days after the latter’s arrival. Combat with other species found within the territories of these birds was observed. Combat with the Bluebird was most frequent but one or more Indications of opposition was noticed with the Flicker, Downy Woodpecker, Acadian Flycatcher, Tufted Titmouse, Robin, and Cardinal.

The males sing persistently and energetically from the time that they arrive on their territories, hoping to attract their mates, but they are not always successful, especially in regions where the species is rare or not very common, and their nest-building brings no occupant. Edward von S. Dingle writes to me that, at Summerton, S. C., a male prothonotary warbler built a nest in a low stub, but no female was ever seen. He sang frequently and remained in the vicinity for several weeks. And Frederic H. Kennard, in far-away Massachusetts, mentions in his notes that he saw one and watehed it for several days, June 16: 20, 1890. “He sang loudly and clearly and sweetly, and seemed to like a particular place by the side of the river, for when I returned later in the day, he was still there, on the other side of the river.” On June 19, he watched him for half an hour. He was always in the same locality. On a later search, no nest or no mate could be found.

Courtship: Brewster (1878a) gives the following full account of this performance:

Mating began almost immediately after the arrival of the females, and the “old, old story” was told in many a willow thicket by the little golden-breasted lovers. The scene enacted upon such occasions was not strikingly different from that usual among the smaller birds; retiring and somexvhat indifferent coyness on the part of the female; violent protestations and demonstrations from the male, who swelled his plumage, spread his wings and tail, and fairly danced around the object of his affections. Sometimes at this juncture another male appeared, and then a fierce conflict was sure to ensue. The combatants would struggle together most furiously until the weaker was forced to give way and take to flight. On several occasions I have seen two males, after fighting among the branches for a long time, clinch and come fluttering together to the water beneath, where for several minutes the contest continued upon the surface until both were fairly drenched. The males rarely meet in the mating season without fighting, even though no female may be near. Sometimes one of them turns tail at the outset; and the other at once giving chase, the pursuer and pursued, separated by a few inches only, go darting through tile woods, winding, doubling, now careering away up among the tree-tops, now down over the water, sweeping close to the surface until the eye becomes weary with following their mad flight. During all this time the female usually busies herself with feeding, apparently entirely unconcerned as to the issue. Upon the return of the conqueror her indifference, real or assumed, vanishes, he receives a warm welcome, and matters are soon arranged between them.

Nesting: The prothonotary warbler and Lucy’s warbler are the only two American warblers that habitually build their nests in cavities, usually well concealed. The norma], and probably the original, primitive, nestling sites are in natural cavities in trees and most nests are still to be found in sllch situations today. The prothonotary is not at all particular as to the species of trees, nests having been found in many kinds of trees, although perhaps a slight preference is shown for dead willow stumps. Nor is it particular as to the size or condition of the cavity, or its location, though quite often choosing one over water or near it. The height above the ground or water varies from 3 feet or less to as much as 32 feet but there are more nests below 5 feet than there are above 10, the height of the majority being between 5 and 10 feet. The size and shape of the cavity are of little concern; if the cavity is too deep, the industrious little birds fill it with nesting material up to within a few inches of the top; sometimes a very shallow cavity is used, so that the bird can be plainly seen from a distance as it sits on the nest. The old deserted boles of woodpeckers or chickadees are favorite nesting sites; the entrances to these have often been enlarged by other agencies, or are badly weathered. In very rotten stumps, the warbiers have been known to excavate partially or to enlarge a cavity.

The nests built by the males in early spring, referred to above, are probably rarely used as brood nests and might be classed as dummy nests. The family nest is built almost entirely by the female, with encouragement and a little help from her mate, who accompanies her to and from the nest and in the search for material; much of the soft, green moss used extensively in the nest is often obtainable from fallen logs and stumps in the vicinity.

Brewster (1878a) mentions a nest taken from a deep cavity that “when removed presents the appearance of a compact mass of moss five or six inches in height by three or four in diameter. When the cavity is shallow, it is of~n only scantily lined with moss and a few fine roots. The deeper nests are of course the more elaborate ones. One of the finest specimens before me is composed of moss, dry leaves, and cypress twigs. The cavity for the eggs is a neatly rounded, cupshaped hollow, two inches in diameter by one and a half in depth, smoothly lined with fine roots and a few wing-feathers of some small bird.”

In Dr. Walkinshaw’s (1938) Michigan nests, “moss constituted the bulk of the nesting material in nearly all cases, completely filling the nest space whether it was large or small. On top of this the nest proper was shaped and a rough lining of coarse grape-bark, dead leaves, black rootlets procured from the river-banks, and poison-ivy tendrils was added. Above this a lining of much finer rootlets, leafstems, and very fine grasses was used.”

In addition to the materials listed above Meyer and Nevius (1943) mention hackberry leaves, halt’s, pine needles, horsehair, and cedar bark in their Tennessee nests. They say that from 6 to 10 days were required for nest constrnction, and that from 3 to 5 days more elapsed before the first eggs were laid. Their four nests were all in birdboxes; one was in an orchard over plowed ground, one over a lotus pond in a wooded ravine, and two were over lily pools near buildings.

Dr. Walkinshaw (1938) publishes a map showing the location of 21 nesting boxes along the winding banks of the Battle Creek River, in Calhoun County, Mich., and writes: “Of the 28 nests found during 1937, 19 were in bird-houses over running water, 6 were in stubs over water (2 of which were over running water), and the other 3 were in natural holes back from the river bank. Of 44 nests found from 1930 through 1937, excluding the 21 in bird-houses, six were over running water in old woodpecker holes, one in a bridge-support in a slight depression, and nine in natural holes over standing water. Seven were in old woodpecker holes from two to a hundred and sixty feet back from the river-bank.”

Many and varied are the odd nesting sites occupied by prothonotary warbiers. Dr. Thomas S. Roberts (1936) writes:

The vagaries of this bird In choosing artificial nesting-places are shown by the positions of the following nests. On the La Crosse railroad bridge: in a cigar-box nailed on the engine-house on top of the draw; on one of the piers; In a metal ventilator-cap four inches in diameter, that had fallen and lodged Just at the point where the draw banged against the pier, and close under the tracks; in a shallow cavity in a piece of slab-wood nailed to a trestle-support close under the road-bed of the railroad; these all far out in the middle of the Mississippi River. Still others are: in a Bluebird box on a low post by a switching-house and busy railroad platform; in a cleft In a pile in the river; in a tin cup in a barn, to reach which the birds entered through a broken pane of glass; in a pasteboard box on a shelf in a little summer-house; in an upright glass fruit jar in a house-boat; and other similar situations. In most cases the birds had to carry the nesting-material long distances, especially to the places on the bridge.

John W. Moyer (1933) relates an interesting story that was told to him by people living in a farm house along the Kankakee River. A pair of these warbiers built their nests and raised their broods for three consecutive seasons in the pocket of an old hunting-coat, hung in a garage; each year the man cleaned out the nest and used the coat in the fall, and the next spring the birds used it again. M. G. Vaiden tells me of a similar case.

Nests have been found in buildings, on beams and other supports. Louis W. Campbell (1930) reports two on shelves in sheds, one in a small paper sack partly filled with staples and another in a coffee can similarly filled. Nests in cans in various situations have been found a number of times, and others have been reported in a tin pail hung under a porch, in a mail box, in a box on a moving ferry boat, in a Chinese lantern on a pavilion, and in an old hornets’ nest.

Dr. Walkinshaw writes to me: “At Reelfoot Lake, Tenn., during July, 1940, I found S nests of the prothonotary warbler, all built a few feet above the water in small natural holes in cypress knees. Evidently these are regular late-summer nesting ~ The knees were farther under water earlier in the season. Most of his 76 Michigan nests were over water, or less than 100 feet from it; but 10 were 300 or more feet away from it and 2 were over 400 feet away. M. G. Vaiden tells me of a pair that nested in the tool box of a logloading machine that was in daily operation, hauling logs.

Eggs: From 3 to 8 eggs have been found in nests of the prothonotary warbler, from 4 to 6 seem to be the commonest numbers, 7 is a fairly common number, and at least 3 sets of 8 have been reported; in the J. P. Norris series of 70 sets are 34 sets of 6, 15 sets of 7, and 2 sets of 8. The eggs vary in shape from ovate to short ovate, and they are more or less glossy. The eggs are undoubtedly the most striking of the warbiers’ eggs, with their rich creamy, or rose-tinted cream, ground color, boldly and liberally spotted and blotched with “burnt umber,” “bay,” “chestnut brown,” and “auburn,” intermingled with spots and undertones of “light Payne’s gray,” “Rood’s lavender,” “violet~~ay,~~ and “purplish gray.” There is quite a variation in the amount of markings, which are generally more or less evenly scattered over the entire egg; some are sparingly spotted and blotched, while others are so profusely marked as almost to obscure the ground color (Harris).

J. P. Norris (1890b),in his description of his 70 sets, describes 2 eggs in each of 2 sets as “unmarked, save for four or five indistinct specks of cinnamon.” These were in sets of 6 eggs each. Pure white, unmarked eggs were once taken by R. M. Barnes (1889). Dr. Walkinshaw (1938) gives the measurements of 78 eggs as averaging 18.47 by 14.55 millimeters; the eggs showing the four extremes measured 20 by 15, 19 by 16, and 17 by 13 millimeters.

Incubation: The eggs are laid, usually one each day, very early in the morning; Dr. Walkinshaw (1941) says between 5: 00 and 7: 00 a. m. in Michigan; Meyer and Nevius (1943), in Tennessee, saw the female enter the nest to lay as early as 5 : 00 a. m. on May 2, and as early as 4: 44 on May 23, remaining in the nest from 28 to 36 minutes on different occasions. The period of incubation is recorded as 12, 131/2, and 14 days by different observers; about 13 seems to be the average, according to Dr. Walkinshaw (MS.), probably depending on conditions and the method of reckoning. Incubation seems to be performed entirely by the female, but the male feeds her to some extent while she is on the nest. Incubation starts the day before the last egg is laid.

Young: Meyer and Nevius (1943) write:

The adults shared feeding duties, and both removed fecal sacks. During the first three days the female steadily brooded the young. One female, observed from 4: 55 to 8: 10 a. in., when the young were one day old, spent a total of 70 minutes off and 155 minutes on the nest. Trips from the nest lasted an average of 8.6 minutes, while periods on the nest averaged 19.4 minutes. * * * At one nest when the young were eight days old, activities were noted during the eight and one-half hours from 8: 30 a. in. to 5: 30 p. in. The young were fed an average of 16 times an hour. ï * * The adults were seen carrying spiders and insects, small green caterpillars frequently being used. Mr. H. P. hams saw a male offer a 10-day old nestling a inayfly. An incubator-hatched bird accepted egg-yolk, ants, ant larvae, crickets, earthworms, and spiders.

They say of the development of the young: “The young on the day of hatching had orange-red skin. The mouth lining was red. Down was distributed over the frontal and occipital areas of the capital tract, spinal tract, femoral, altar, and humeral tracts. Feather sheaths of the alar tracts penetrated the skin the first day after hatching. On the second day after hatching the eye-slits began to open. Feather sheaths of the humeral, femoral, and crural tracts emerged on the third day; those on the dorsal and ventral tracts emerged on the fourth day, and those of the capital and caudal tracts on the fifth day. On the fifth day the sheaths began breaking.” During the next five days the young developed rapidly and became more and more active, and on the tenth day began to leave the nest.

Young observed by Dr. Walkinshaw (1914) at Reelfoot Lake “averaged 11 days of age when leaving the nest in 1939, while 21 young in Michigan during 1939 and 1940 remained in the nest for a period of 103A days.” Of the comparative nesting success in the two localities, he says:

In Michigan from 1930 through 1940, 121 nests of the Prothonotary Warbler were observed. Only 28, or 23.14 per cent, were successfuL Out of 413 eggs, 159 (38.47 per cent) hatched and 100 young were fledged (.87 per total nest; 3.78 per successful nest). The fledgling success was 25.66 per cent of eggs laid. More failures In Michigan resulted in more nestings by individual birds.

In Tennessee during 1939, 30 nests were observed until terminated or successful; 19 were successful (63.33 per cent) while out of 139 eggs, 78 hatched and all the young lived to leave the nest or 56.11 per cent fledging success of eggs laid; 2.6 young were fledged per total nest; 4.1 per successful nest.

He also notes that in Michigan the species is typically single-brooded if the first nesting is successful, but that in Tennessee it is typically double-brooded.

Plumages: According to Dr. Dwight (1900) the natal down, located as indicated above, is brownish mouse-gray. Ridgway (1902) gives rather the best description of the juvenal plumage as follows: “Pileum, hindneck, back, and scapulars dull olive-greenish; wingcoverts, tertials, rump, and upper tail-coverts slate-gray, tinged with olive, the middle and greater wing-coverts narrowly tipped with light olive-greenish, producing two very indistinct bands; secondaries, primaries, and rectrices as in adults; sides of head pale yellowish olive; chin, throat, and chest dull light grayish olive, darkest on chest rest of under parts dull white, passing on sides and flanks into olive-grayish.”

In very young birds, according to Dr. Dwight, there is a variable amount of brownish wash on the back, which fades out to gray. And Dr. Chapman (1907) says that the white on the inner webs of the tail feathers is more restricted than in adults and more or less mottled with blackish. This first plumage is followed in June and July by a partial postjuvenal molt involving all the contour plumage and the wing coverts but not the rest of the wings or the tail. The young bird now becomes a golden swamp warbler, the young being nearly like the adults, the females being considerably duller in color than the males and having less white in the tail. The crown and hind neck in both sexes, bath old and young, are washed with dusky or olive in the fall. Spring plumages are produced by very slight wear without molt. There is one complete, annual molt in late summer.

Food: Very little seems to have been recorded on the food of the prothonotary warbler. It is evidently highly insectivorous, obtaining most of its food from the trunks and branches of trees and shrubs and from fallen logs. Brewster (1878) says: “This Warbler usually seeks its food low down among thickets, moss-grown logs, or floating debris, and always about water. Sometimes it ascends tree-trunks for a little way like the Black-and-White Creeper, winding about with the same peculiar motion.”

Dr. Roberts (1936) lists “ants, and other insects and their larvae,” as its food. Some of the food of the young is mentioned above, most of which is doubtless included in the food of the adults. Spiders, beetles, mayflies, and other insects should be included, as well as many caterpillars and the larvae of water insects. Audubon (1841) says: “It often perches upon the rank grasses and water plants, in quest of minute molluscous animals which creep upon them, and which, together with small land snails, I have found in its stomach.”

Behavior: Brewster (1878a) observes:

When seen among the upper branches, where it often goes to plume its feathers and sing in the warm sunshine, it almost invariably sits nearly motionless. Its flight is much like that of the Water-Thrush (either species), and is remarkably swift, firm, and decided. When crossing a broad stream it is slightly undulating, though always direct. ï * *

In general activity and restlessness few birds equal the species under consideration. Not a nook or corner of his domain but is repeatedly visited through the day. Now he sings a few times from the top of some tall willow that leans out over the stream, sitting motionless among the yellowish foliage, fully aware, perhaps, of the protection afforded by its harmonizing tints. The next moment he descends to the cool shades beneath, where dark, coffee-colored water, the overflow of the pond or river, stretches back among the trees. Here he loves to hop about on floating drift-wood, wet by the lapping of pulsating wavelets; now following up some long, inclining, half-submerged log, peeping into every crevice and occasionally dragging forth from its concealment a spider or small beetle, turning alternately his bright yellow breast and olive back towards the light; now Jetting his beautiful tail or quivering his wings tremulously, he darts off into some thicket in response to a call from his mate; or, flying to a neighbor. ing tree-trunk, clings for a moment against the mossy bole to pipe his little strain or look up the exact whereabouts of some suspected insect prize.

Voice: The same gifted writer and careful observer (Brewster, 1878) gives the following good account of the distinctive song of this warbler:

The usual song of the Prothonotary Warbler sounds at a distance like the call of the Solitary Sandpiper, with a syllable or two added,: a simple peet, tweet, tweet, tweet, given on the same key throughout. Often when the notes came from the farther shore of a river or pond we were completely deceived. On more than one occasion, when a good opportunity for comparison was offered by the actual presence of both birds at the same time, we found that at the distance of several hundred yards their notes were absolutely undistinguishable; nearer at hand, however, the resemblance is lost, and a ringing, penetrating quality becomes apparent in the Warbler’s song. It now sounds like peet, teweet, tsweet, tsweet, or sometimes tweet, tr-sweet, tr-sweet, tr-sweet. ‘When the bird sings within a few yards the sound is almost startling in its intensity, and the listener feels inclined to stop his ears. The male is a fitful singer, and is quite as apt to he heard in the hot noontide or on cloudy days, when other birds are silent, as during the cool morning and evening hours. The ordinary note of alarm or distress is a sharp one, so nearly like that of the Large-billed Water Thrush (Siurus motacilla) that the slight difference can only he detected by a critical ear. When the sexes meet a soft tchip of recognition common to nearly all the Warbiers is used. In addition to the song above described the male has a different and far sweeter one, which is reserved for select occasions,: an outpouring of the bird’s most tender feelings, intended for the ears of his mate alone, like the rare evening warble of the Oven-Bird (Siurus auricapillus). It is apparently uttered only while on the wing.

Although so low and feeble as to be inaudible many rods away, It is very sweet, resembling somewhat the song of the Canary, given in an undertone, with trills or “water-notes” interspersed. The flight during its delivery is very different from that at all other times. The bird progresses slowly, with a trembling, fluttering motion, its head raised and tail expanded. This song was heard most frequently after incubation had begun.

Dr. Roberts (1986) refers to this flight song, as delivered “after the manner of the Maryland Yellow-throat, * * * consisting first of the usual rapid monotone of five or six notes and ending with a pleasing, varied warble, full and strong in some of its notes and far sweeter than the usual utterance.”

Dr. Walkinshaw (1938) says of the usual song: “Uttered at the rate of five or six times per minute, the song lasts slightly over one second. It is given all day long from the time of arrival until the young have left the nest and has been hcard as late as the 16th of August (1931). The frequency is much greater during the early nesting season and during the earlier hours. During midday on warmer days the number of times per hour seems much less. Later, from four until near sundown, it again increases. During late nesting, when the young are about to leave the nest, the rate again decreases, but it is heard several days after the young leave the nest.” Aretas A. Saunders tells me that the songs are pitched at C”” or B”‘, and the call note, tseek, at A”‘.

Field marks: The golden swamp warbler could hardly be mistaken for anything else. The rich, brilliant yellow of the head and breast, sometimes almost orange on the head, only slightly paler in the female, the absence of wing bars, and the large amount of white in the tail will distinguish it.

Enemies: Dr. Walkinshaw (1941) says that the house wren is a serious competitor with the prothonotary warbler in Michigan, contending with it for nesting sites in the bird-boxes.

The cowbird is a persistent enemy of this warbler in spite of its hole-nesting habits; perhaps if the warbler nested in deeper holes it might find some relief from this pest. Among 70 sets of eggs of this warbler in the J. P. Norris collection, 18 contain cowbirds’ eggs. Dr. Friedmann (1929) found no less than 36 records of such parasitism in the literature, and says: “As many as four eggs of the Cowbird have been found in a single nest together with four of the Warbler’s. There are several cases on record of doubled-storied nests of this bird, with a Cowbird’s egg buried in the lower story. Such cases are, however, not cornmon, and usually the Warbler seems to make no attempt to get rid of the strange eggs.” E. M. S. Dale wrote to me of a nest, found near Toronto in 1933, that contained seven eggs of the cowbird and none at all of the warbler! Snakes sometimes destroy the eggs or young.

Fall: Dr. Walkinshaw (1938) says that “the majority of the Prothonotaries leave our rivers [Michigan] by the second or third of July. One may canoe some years a good many miles during the latter part of July or the early part of August without finding a single Prothonotary, whereas in other years many groups can be found. The majority evidently are early migrants. Very few remain until late August or early September, the latest date being September 9, 1934, at Battle Creek.”

The 1931 A. 0. III. Check-List states that this warbler apparently crosses the Gulf of Mexico in migration “and is not found in Mexico north of Campeche,” but probably some migration is along the coast of Texas and Mexico, as suggested by George G. Williams (1945).

Dr. Chapman (1907) says: “The route of the Prothonotary Warbler in its fall migration is interesting; the breeding birds of the Middle Atlantic States apparently pass southwest to northwestern Florida and then take a seven-hundred-mile flight directly across the Gulf of Mexico to southern Yucatan, instead of crossing to Cuba and thence to Yucatan.”

Alexander F. Skutch writes to me: “Unrecorded from Guatemala, the prothonotary warbler is a rare bird of passage and very rare winter resident in the more southerly portions of Central America. When Carriker published his list of Costa Rican birds in 1910, he had a few records from the highlands: apparently of migrating birds: and from the Pacific lowlands, but none from Caribbean lowlands. But on March 4, 1934, I found it not uncommon at Puerto Lim6n, where I saw one among the royal palms in Vargas Park, and several among the shrubbery about the outlying cottages, all within a hundred yards of the Caribbean Sea. It has been recorded a number of times from the Canal Zone, but it is not common there. It is almost always seen in the vicinity of water.”

Winter: Apparently the main winter range is in Colombia and perhaps Venezuela. Referring to Magdalena, Colombia, P. J. Darlington, Jr. (1931), writes: “The Prothonotary Warbler swarms during the winter in the mangroves at Sevillano and in the fresh swamps at Cienaga. It was seen also in bushes on the sea beach at Donjaca September 15, and along the Rio Frio River in the edge of the foothills, where it was especially conimon in February. The birds usually occur near water, but numbers were noted again and again in yellow-flowering, acacia-like trees on the border of stump land and dry forest, far from water.”

DISTRIBUTION
Range: Eastern United States to northwestern South America.

Breeding range: The prothonotary warbler breeds north to southeastern Minnesota (Cambridge, Lake Pekin, and La Crescent); central Wisconsin (New London and Shiocton); southern Michigan (Hesperia, Lansing, and Ann Arbor); northern Ohio (Toledo and Cleveland) ; extreme southern Ontario (Rondeau) ; western New York (Buffalo and Oak Orchard) ; northern West Virginia (Parkersburg); central Maryland (Seneca and Bowie) ; and southern Delaware (Gumboro). East to southern Delaware (Gumboro); eastern Virginia (Dyke, near Alexandria, and Dismal Swamp); and the Atlantic coast to central Florida (Lake Gentry and Padgett Creek). South to central Florida (Padgett Creek and possibly Puntarossa); the Gulf coast to southeastern Texas (Cove, Houston, and Bloomington). West to central Texas (Bloomington, Fort Worth, and Gainesville); central Oklahoma (Norman and Oklahoma City); eastern Kansas (Emporia and Manhattan); northwestern Iowa (Lake Okoboji); and southeastern Minnesota (Rochester, Red Wing, and Cambridge).

The prothonotary warbler has been recorded as casual or accidental west to southeastern Nebraska (Powell and Lincoln); southeastern South Dakota (Yankton and Sioux Falls) ; and central Minnesota (Brainerd). North to southern Ontario (London and Hamilton); central New York (Ithaca) ; Massachusetts (Northampton, Amherst, and Concord) ; New Hampshire (Concord) ; and Maine (Matinicus Island and Calais).

Winter range: The winter home of the prothonotary warbler is in Central America and northwestern South America where it has been found north to northwestern Costa Rica (Bolson) ; Nicaragua (Escondido River). East to northwestern Venezuela (M~rida and Encontrados); and western Colombia (San Jos~ de Cucuta and Vilaviej a). South to southwestern Colombia (Villavieja); and northwestern Ecuador (Esmeraldas). West to northwestern Ecuador (Esmeraldas); western Colombia (Antioquia); western Panama (Paracote and David); and Costa Rica (Puntarenas and Bolson). It has been reported to occur in winter in Campeche and on Cozumel Island, Mexico, and casually or accidentally in Cuba (Habana), Jamaica, and St. Croix, Virgin Islands.

Migration: The probable route of the prothonotary warbler between its summer and winter homes is across the Gulf of Mexico, from the Yucatan peninsula where it occurs in both spring and fall migration. The casual or accidental occurrences of this warbler in Cuba (Habana); Jamaica; and St. Croix, Virgin Islands, are in migration.

Late dates of spring departure are: Colombia: Villaviej a, February 5. Panama; Canal Zone: Barro Colorado, March 10. Nicaragua: Eden, March 23. Quintana Roo: Cozumel, April 6. Cuba: Habana, April 4.

Early dates of spring arrival are: Yucat~in: M~rida, March 28. Jamaica: Black River, February 28. Cuba: Habana, March 31. Florida: Pensacola, March 18. Alabama: Booth, April 4. Georgia: Fitzgerald, March 21. South Carolina: Yemassee, March 27. North Carolina: Greenville, April 6. Virginia: Suffolk, April 10. Mississippi: Gulfport, March 18. Louisiana: Morgan City, March 10. Texas: Cove, March 28. Arkansas: Huttig, March 31. Missouri: St. Louis, April 17. Kentucky: Bowling Green, April 5. Illinois: Murphysboro, April 17. Ohio: Berlin Center, April 18. Michigan: Grand Rapids, May 3. Iowa: Iowa City, April 26. Wisconsin: Madison, May 2. Minnesota: Red Wing, May 7. Oklahoma: Tulsa, April 2. Kansas: Manhattan, April 26. Nebraska: Blue Springs, April 30.

Late dates of fall departure are: Nebraska: Watson, September 1. Oklahoma: Oklahoma City, September 14. Texas: Kemah, September 11. Wisconsin: Racine, September 22. Iowa: Sioux City, August 31. Michigan: Three Rivers, September 13. Ohio: Columbus, October 5. Illinois: Oak Park, October 17. Kentucky: Lexington, October 6. Tennessee: Elizabethton, October 19. Louisiana: Monroe, October 8. Mississippi: Deer Island, September 27. North Carolina: Raleigh, August 26. South Carolina: Charleston, September 17. Georgia: Atlanta, October 8. Yucat~n: Chich~n-Itz~, October 18.

Early dates of fall arrival are: Florida: Fort Myers, August 8. YucatAn: Chich~n-Itz~, October 7. Honduras: Tela, September 8. Nicaragua: Rio Escondido, September 2. Costa Rica: Bonilla, August 28. Panam~: Obaldia, September 15. Colombia: Gaira, Sep~ tember 11.

Banding records: Banding provides a hint as to the life-span of the prothonotary warbler. One banded as an immature on June 16, 1940, in Convis township, Calhoun County, Mich., was color banded when it returned to the same place in 1942. Subsequently it was identified by the colored band on May 14, 1944, and May 10, 1945.

Casual records: The prothonotary warbler was reported at Nassau, Bahamas, on August 29, 1898. It has been twice reported at Bermuda: one shot from a flock in the fall of 1874, and another specimen collected in November 1903. A single bird was observed at Mammoth Hot Springs, Yellowstone Park, Wyo., on September 10,1931. There are two records for Arizona. On May 1, 1884, a specimen was taken near Tucson at an altitude of 2,300 feet, the highest record of the species in the United States. Another specimen was taken September 8, 1924, at Cave Creek, 4 miles northeast of Paradise in the Chiricahua Mountains.

Egg dates: Florida: 8 records, April 18 to May 9; 5 records, April 28 to 30.

Illinois: 79 records, May 6 to June 21; 46 records, May 20 to June 4, indicating the height of the season.

Iowa: 56 records, May 15 to June 26; 36 records, May 27 to June 6 (Harris).