Swamp Sparrow

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

“In this moderately well marked race,” (Godfrey, 1949) “breeding adults differ from Melospiza georgiana georgiana in their paler upper parts, the browns of back and rump averaging grayer, the pale dorsal feather edgings whiter and apparently broader. Autumn specimens of ericrypta are distinguishable by their paler dorsal and rump coloration, and by the paler feather edgings of the back which provide more contrast with the black dorsal streaking than in georgiana, which average darker and duller above. In juvenal plumage the differences are somewhat less obvious but ericrypta averages paler.” Wetmore (1940) finds that Oberholser’s (1938) statement that the western birds are smaller is not confirmed by measurements.

DISTRIBUTION

Range: Southern Mackenzie, northern Ontario, central Quebec, and Newfoundland south to central Mexico, the Gulf coast, and northeastern Florida.

Breeding range: The northern swamp sparrow breeds from southwestern and central southern Mackenzie (Fort Norman, Hill Island Lake), northern Saskatchewan (Lake Athabaska), northern Manitoba (Churchill), northern Ontario (Fort Severn, Attawapiskat Post), central Quebec (Paul Bay, Mingan Island), and Newfoundland (Pistolet Bay, St. John’s) south to northeastern British Columbia (Nulki Lake, Tates Creek), central Alberta (Red Deer), southern Saskatchewan (Indian Head), southern Manitoba (Margaret, Indian Bay), northeastern North Dakota (Fargo), northern Minnesota, western and central Ontario (Big Fork, Chapleau), and south-central Quebec (Lake St. John, Gasp6 Peninsula).

Winter range: Winters south to Jalisco (Ocotlán), Tamaulipas (Altamira), eastern Texas (Beaumont), southern Louisiana (Buras), southern Mississippi (Cat Island), southern Georgia (Grady County, Folkston), and northeastern Florida (Gainesville, Palatka). Northern limits in winter imperfectly known; recorded from Tennessee (Nashville), South Carolina (Anderson County), Virginia (Manassas, Alexandria, Mount Vernon), and Massachusetts (Wayland); casually to northwestern Oregon (Tillamook), California (Morro Bay; San Diego County; Riverside, Salton Sea), central Nevada (Ruby Lake), and southern Arizona (Tucson).

Egg dates: Ontario: 28 records, May 19 to July 25; 14 records, May 30 to June 9.

Quebec: 26 records, May 9 to June 26; 18 records, May 20 to June 2.

SOUTHERN SWAMP SPARROW

MELOSPIZA GEORGIANA GEORGIANA (Latham)

Contributed by DAVID KENNETH WETHERBEE

HABITS

Because the specimen he described came from Georgia, John Latham named this species Fringilla georgiana in 1790. Known earlier by William Bartram as the “reed sparrow,” it was first called the swamp sparrow by Alexander Wilson when he redescribed it as Fringilla palustris (swampy) in 1811. Recognizing its close taxonomic relationship to the song and Lincoln’s sparrows, Spencer Fullerton Baird placed all three species in his new genus Melospiza (song finch) in 1858. Because of the similarity of their juvenal plumages, Richard Graber (pers. comm.) would unite Melospiza and Passerelle, as J. M. Linsdale (1928) and others have recommended on morphological and behavioral grounds. Graber considers georgiana, on the basis of plumage characteristics, to be evolutionarily the “most advanced” member of the combined genera. Though this group is famous for geographical variation in color and size, only three subspecies of the swamp sparrow are recognized by the current (1957) A.O.U. Check-List: the nominate southern race, georgiana, a lighter northern race, ericrypta, and a darker coastal race, nigrescens. The habits of all three are treated together here.

In comparison to its much-studied congener, the song sparrow, the swamp sparrow is rather poorly known, a simple consequence of the ankle- to waist-deep morass that is its usual habitat. As E. H. Forbush (1929) aptly expresses it:

The Swamp Sparrow is not a public character. He will never be popular or notorious. He is too retiring to be much in the public eye, and too fond of the impassable bog and morass to have much human company; and so he comes and goes unheralded and to most people unknown. He is the dark little bird that fusses about in the mud when spring floods have overflowed the wood roads, or slips through the grasses on marsh-lined shores of slow-flowing, muddy rivers. Any watery, muddy, bushy, grassy place where rank marsh grasses, sedges and reeds grow—any such bog or slough where a man will need long rubber boots to get about—is good enough for Swamp Sparrows. In such places they build their nests. But in migration they may appear almost anywhere, though seldom distinctly seen and recognized by ordinary observers, because of their retiring habits. When they are looked for, they sneak about, mostly under cover, and hardly show themselves sufficiently for identification, but if the observer apparently takes no interest in their whereabouts and sits quietly down, curiosity may overcome their suspicions and bring them into view.

Spring: The “swamp song sparrows” are first heard in the breeding range in March, and they reach a numerical peak in New England in mid-May. At this time they can be found in many swamps where there will be none during the nesting season. The sparse northern wintering population is probably migratory; a bird banded at Athol, Mass. in January remained at the banding station until April when it disappeared (Bagg and Eliot, 1937). One banded at Lisle, Ill., May 1,1931, was found dead a year and a day later in Clarion, Mich.

P. L. Hatch (1892) states, perhaps without critical evidence, that the females arrive a few days later than the males in spring.

LeRoy C. Stegeman (1955) notes that swamp sparrows are lighter in weight in the spring than they are in the fall. This condition, the reverse of that in its near relative, the song sparrow, he attributes to the fact that the swamp sparrow is more insectivorous and less granivorous than the song sparrow.

Nesting: The swamp sparrow breeds in fresh water marshes, swamps, bogs, and wet meadows, and about the low swampy shores of lakes and streams, more rarely in coastal brackish meadows. Usually only a few pairs occupy a given locality, but occasionally it seems to nest semi-colonially where conditions are suitable. Chandler S. Robbins (1949) reports a breeding density of 21 per 100 acres (2 in 9½ acres) of “open hemlock-spruce bog” in Maryland. J. W. Aldrich (1943) determined that in northeastern Ohio it shares seasonal predominance with the red winged blackbird and Virginia rail in the Decodon-Typha Associes; with the short-billed marsh wren, redwinged blackbird, and Virginia rail in the Juncus-Scirpus Associes; with the song sparrow, yellowthroat, and yellow warbler in the Nemopanthus-Alnus Associes; with the song sparrow, American goldfinch, robin, yellow warbler, yellowthroat, redwinged blackbird, kingbird, and Traill’s flycatcher in the Cephalanthus-Alnus associes; and with the song sparrow and yellowthroat in the Chamaedaphne-calyculata Consocies. G. M. Allen (1925) states more simply that in most New England swamps “The Swamp Sparrows are found in the inner grassy ring; Song Sparrows and Yellowthroats in the bushy border.” George M. Sutton writes me that he believes, from observations at the George Reserve in Michigan that this species requires mixed vegetation, a more complete overhead shelter than a pure stand of Chamaedaphne affords, and that adequate nest-sites are not provided by a pure stand of cat-tails.

Practically nothing is known of territorial behavior in this species, nor has its courtship been described. The male generally sings from a conspicuous position on an alder or willow or cat-tail, and often adopts this perch as its habitual singing place. While singing the bird spreads its tail noticeably. G. M. Sutton writes me that he once observed a male chasing a female with a dry grass-blade in her bill.

Sutton (1928) based the following generalized description on some 66 nests he found in the Pymatuning Swamp area of Pennsylvania:

Nests were almost never placed on the ground, but were built between the cat-tail stalks, or upon the bent-down clumps of stalks and leaves, and were often completely hidden from above by the broad, dead leaf-blades. Entrances to the nests were almost always from the side, and rarely from above. The material of the lining varied but little. It was always of fine grasses, and not varied with plant-fiber, roots, or hair, as might have been expected. The material forming the foundations of the nests was often coarse and bulky, and some of the structures were huge, sprawling affairs. Nests were often built directly above the water, where the depth varied from six to twenty-four inches, and were usually built about a foot or more above the surface.

In the less alkaline swamps I have found many nests built in green sedge tussocks of Carex. The broad bushy flood-plain along the meandering Quabog River in central Massachusetts, where literally thousands of swamp sparrows breed, is the only place I have found them nesting consistently in bushes, and usually at heights reached only by standing in a boat.

Though the foundation is occasionally huge and sprawling, the nest proper is usually smaller than that of the song sparrow, being on the average 4.0 inches in outside diameter, with the inside cup 2.4 inches across and 1.5 inches deep. All those I have found have had the foundation and the thick outer cup built entirely of tightly woven coarse dead marsh “grasses,” and the inner cup of fine round grass stems, often still showing green. Isaac E. Hess (1910) states that each of four nests he found in Illinois “had an appendage or handle constructed of grass stems protruding from one side about three inches.” I also have noticed this characteristic loose tag on many nests. The entrance to the nest is characteristically from the side. The parents circled a Chardoneret banding trap I placed over a nest of fledglings in frustration for an hour until I rigged an inclined stick from a nearby perch that led them to the top entrance.

P. L. Hatch (1892) writes that the nest is “jointly built” by the pair, but this is probably an uncritical observation. Most of the evidence suggests that, as in most of the closely related sparrows, nest building in the swamp sparrow is entirely or almost entirely by the female.

Eggs: (The data refer to the species as a whole.) The swamp sparrow lays from 3 to 6, usually 4 or 5 ovate and slightly glossy eggs. The ground color of freshly laid eggs is usually “pale Niagara green,” but this pales out to a greenish-white upon exposure. They are spotted, blotched, clouded, and frequently marked with scrawls of reddish browns such as “Verona brown,” “Prout’s brown,” “Brussels brown,” or “Argus brown,” with undermarkings of “pale neutral gray.” They vary considerably, but are generally boldly marked, and practically indistinguishable from those of the song sparrow, except in a series it is noticeable that the blotchings and cloudings are heavier; also they are frequently marked with clouded scrawls and they average slightly smaller. The measurements of 50 eggs average 19.4 by 14.6 millimeters; the eggs showing the four extremes measure p21.8 by 5.1, 20.0 by 16.4, 17.8 by 15.0, and 19.3 by 13.1 millimeters.

In one clutch that I incubated artificially, the eggs floated when tested 10 days before hatching. The complete clutch of four eggs weighed 8.25 grams, and the individual eggs from 1.85 to 2.15 grams. I found them more difficult to candle than the eggs of many song birds. The three young that hatched averaged 1.46 grams apiece at hatching.

Two clutches are laid each year and sometimes more, particularly when early clutches are destroyed by flooding or by predators.

Young: Incubation is apparently by the female alone, at least I have never seen the male incubate. I have, however, often seen the male feed the slightly smaller and duller female on the nest while she brooded. Her mouth lining appeared to be the same orange color as that of her 4-day-old young.

How well the length of the incubation period has been measured is questionable. Lynds Jones (1892) gives it as 13 days, Ora W. Knight (1908) as 12 to 15 days, T. S. Roberts (1936) as 12 to 13 days. The three of a clutch of four eggs that hatched successfully in my incubator hatched over an interim period of 12 plus or minus 8 hours; the fourth egg did not hatch.

During early incubation the female slips off the nest quietly and unobtrusively while the intruder is still some distance away. Later she waits to be flushed and scolds the intruder busily and boldly. At one nest in advanced incubation that was tipped badly by the differentially growing substrate, the female returned to incubate immediately after I righted it; indeed she seemed as oblivious to my presence in my crude blind as she was to the green frog croaking beside her. Her attentive periods varied from 6 to 15 minutes, her inattentive periods from 11 to 34 minutes. On hot days she spent much of her attentive time sitting high as though to shade the eggs, although no direct sunshine reached the nest. Her departure was sometimes in response to calls of the male, and sometimes without apparent external provocation, though there was usually vocal communication between the pair whenever she left or returned. Her return to the nest was often noisy.

Nothing has been written of nest sanitation, which probably does not differ from that in the song sparrow. G. M. Sutton writes me that he found bits of shell in a nest after the young had fledged, suggesting that the shells may sometimes be crushed rather than carried away by one of the adults.

The chicks hatch with their eyes closed and are very helpless. They make no sound as they gape for food. The inside of the mouth is pink with a very pale yellowish border. The pinkish skin is so transparent the viscera and blood vessels show clearly through the abdomen wall. The tiny egg tooth is about 1 millimeter from the tip of the bill. The upper mandible is pigmented sooty gray anteriorly; the toenails are horn color. The flight feather tracts show pigmentation where the feathers will appear. As the young grow older their mouth lining becomes much brighter orange with a yellow border than in the newly-hatched fledglings.

Fl. H. Forbush (1920) states:

The young ordinarily remain in the nest about 12 or 13 days, if undisturbed. Swamp Sparrows nest near water so frequently that the callow young in their first attempts at flight are likely to fall into it and struggling as they do on the surface, they sometimes fall a prey to large frogs, fish or turtles. The following from one of my note hooks shows how one little bird bravely struggled to safety: Concord, August 28, 1907. This morning early as I stood on the river bank, a bird flying toward me fell and struck the water about half way across the stream. Immediately it fluttered swiftly along on the calm surface of the water for about a rod, and then, apparently exhausted and unable to raise itself from the water, it lay there for a few seconds, head under and tail a little raised. I looked to see some fish seize it, but no! Suddenly by a vigorous struggle it raised its body clear of the water and fluttered almost ashore, alighting on the pickerel weed at the water’s edge. A few minutes later, having regained its breath and courage, it flew up into the bushes, and I saw that it was one of a brood of young Swamp Sparrows in juvenal plumage, which were flitting along the shore.

G. M. Sutton (1935) presumes that the young leave the nest “on or about their ninth day.” I have found them still in the nest on the 7th day but gone on the 11th day.

Plumages and molts: The natal down is blackish brown. Seven specimens had neossoptiles one-half inch long with the following average distribution: coronal region 9, occipital 4, mid-dorsal 6, upper pelvic 1, lower pelvic 6, femoral 8, scapular 5, greater secondary coverts 7, ventral abdominal (these were white) 3. Sporadic pterylal loci were the posterior orbital region, the distal middle secondary coverts, and the proximal secondaries.

To speak of a postnatal molt is a misnomer, as no passerine bird actually “molts” its natal down. The loss of neossoptiles is by abrasion, a process which, although inevitable, is an accidental external phenomenon of a different order than physiological molt. Some loss of neossoptiles is postponed until the first sensu strictro molt, when the juvenal plumage is replaced.

Dwight (1900) describes the juvenal plumage as follows: “Above, cinnamon-brown, dull chestnut on the crown, streaked with black. No obvious median crown stripe. Superciliary line olive-gray duskily spotted. Wings and tail black, edged largely with chestnut, the wing coverts and tertiaries paler. Below, dull yellowish white washed with deep buff on. sides of chin, across jugulum, on sides, flanks and crissum and narrowly streaked with black except on the chin and mid-abdomen. Bill and feet pinkish buff, the former becoming dusky, the latter sepia-brown.” This plumage is similar to that of the song sparrow, but darker expecially on the crown, more washed with buff below, and more narrowly streaked with deeper black on the throat. Richard R. Graber (l9~5) notes that birds of this genus retain the juvenal plumage “for a rather long period by comparison with most migratory passerines.”

The first winter plumage is acquired by a partial postjuvenal molt that starts the end of August and involves the body pumage and wing coverts, but not the flight feathers; G. M. Sutton (1935) says possibly the tail. Dwight (1900) describes this garb as:

“Above, similar to the previous plumage, the back and the lateral crown stripes showing more chestnut; a grayish nuchal band. Below, unlike previous plumage, grayish white, cinereous on throat obscurely streaked with a darker gray, washed on the flanks and often on the breast with olivaceous wood-brown obscurely streaked or spotted with clove-brown. Rictal and submalar streaks black bordering a grayish or yellow tinged chin. Superciliary line clear olive-gray or yellow tinged; postocular streak black; auriculars bistre.”

E. G. Rowland (1928) made many observations on fall birds probably in their first but some possibly in their second winter plumage, that showed abonormal amounts of yellow coloring (xanthochromatism). He summarizes the literature on this peculiar color phase, which was first figured by Baird, Brewer and Ridgway (1874) who named it Passerculus caboti after the collector, Dr. Samuel Cabot, Jr. E. G. Rowland (1925) and L. B. Bishop (1889) also describe melanistic individuals, and J. H. Sage (1913) and A. T. Wayne (1922) describe partial albinos. J. Dwight (1900) continues:

“First Nuptial Plumage acquired by a partial prenuptial moult which involves chiefly the crown, chin and throat, but not the wings nor the tail. The amount of renewal varies according to individual, and may be quite extensive; a few feathers of most of the body tracts are usually renewed. Early April specimens from the south show the prenuptial moult in progress. The chestnut cap with black forhead, white chin, and clear cinereous gray of the throat, sides of head and neck are assumed, and a nearly complete renewal is indicated in some cases judging by the freshness of the feather borders.” Many adults of both sexes lack the reddish brown cap in the spring and have the entire top of the head striped with black and reddish brown with a median gray stripe as in winter plumage. This may represent a first-year nuptial plumage.

The adult winter plumage according to Dwight is “acquired by a complete postnuptial moult in August and September. Practically indistinguishable in many cases from first winter, but usually with more chestnut on the crown, the superciliary line and sides of neck a clearer darker gray, the chin not yellow tinged but white and a grayer cast of plumage everywhere perceptible.”

Mean body weights are given in grams as 17.61 (Wetherbee, 1934), 15.88 (Stewart, 1937), and 18.5 ±2.49 (Hartman, 1946). G. B. Becker and J. W. Stack (1944) give the average temperature of two birds as 110.2° F.

Food :  The swamp sparrow is the most highly insectivorous species in its genus. This is reflected in the reduced size of its skull and bill and bulk of jaw muscle in comparison to those of the seed-cracking song sparrow (Beecher, 1951). Banders note its absence from grain-baited traps during the nesting season (Commons, 1938). Martin, Zim, and Nelson (1951) show its diet to be 55 percent insects in winter, 88 percent in spring and early summer. “Beetles, ants and other Hymentoptera, caterpillars, grasshoppers, and crickets appeared most commonly as items in the insect part of the diet.” In late summer and fall the diet becomes 84 percent to 97 percent granivorous, with seeds of sedges, smartweed, panicgrass, and vervain heading the list. Sylvester D. Judd (1901) writes: “[It] takes more seeds of polygonums than most birds, and eats largely of the seeds of the sedges and aquatic panicums that abound in its swampy habitat. The giant ragweed (Ambrosia trifida) is also well represented in its stomach contents.”

Thomas Nuttall (1840) noted it ate “the smaller coleopterous kinds” of insects, as did I in my examination of nestling stomachs. The ready recognizableness and relative indestructibility of the chitinous remains of Carabid and Curculionid beetles perhaps biases uncritical examinations. Forbush (1929) credits this species with “control over the increase of such marsh insects as the army worm.” C. C. Abbott (1895) describes the birds picking at dead drying herring, and A. H. Howell (1932) mentions their coming to bread crumbs at one of his camps in Florida.

Voice: F. H. Forbush (1929) describes the swamp sparrows voice as: ‘Call note a chink, chip or cheep, with a metallic ring; song weet-weet-weet-weet-weet, etc., a little like that of Chipping Sparrow, but less dry, louder, a trifle more musical and more varied; also a limited variety of twittering notes.” F. Schuyler Mathews (1904) calls the song a monotonic chip repeated in rapid succession with “a very perceptible accelerando.” Aretas A. Saunders (1935) says “Some songs are double; that is, notes are sung on two pitches at once, the higher notes being slow and sweet in quality, and the lower notes faster and somewhat guttural. There are generally three notes of the lower part to one of the upper. The two notes are harmonious and usually about a third apart in pitch.” He states further (in Roberts, 1936) “If one listens carefully to a number of these birds on their breeding grounds he will soon be likely to find one that sings, “tolit lit lit lit” etc., and with it a lower “tururur tururur tururur” about two or two and a half tones below the upper notes. From a distance the higher note is usually the only one audible, whereas near the bird only the low one can be heard, and at a medium distance both are heard at once.” This peculiar anatomy of the swamp sparrow song lends itself to ventrioquial effects.

The male sings in spring from a few special prominent perches on its territory, with tail expanded and evidence of great effort apparent over all its body. T. S. Roberts (1936) claims: “Occasionally the Swamp Sparrow indulges in a flight song, when it rises a few feet in the air and utters a brief, ecstatic jumble of notes surprisingly unlike the usual simple, broken trill.” However E. P. Bicknell (1884) classes the species among those “with which aerial song-flight appears to be only occasional or exceptional.”

The song of this species is one of the first to come from the swamps on summer mornings, and it is often heard past midnight. Indeed M. G. Brooks (1930) notes that “On moonlit nights this bird sings as freely as in the daytime.” G. M. Sutton writes me: “On June 24, 1946, I heard the first Swamp Sparrow song of the day (a full ringing song) at 3:40 a.m., the second at 3:45, and so many immediately thereafter that I felt sure the whole population must have been awake by 3:50, despite the darkness. While spending the night of July 9-10, 1946, awake in a blind at a Whip-poor-will nest, I heard the latest Swamp Sparrow song of the evening at 9:05 o’clock, fully five minutes later than the last song of the veery. * * * In late summer the songs were all delivered from well down in the cat-tails or shrubbery rather than from prominent song-perches.”

E. P. Bicknell (1885) gives the following account of late summer and fall singing in the Riverdale, New York City area:

The song of the Swamp Sparrow comes up from the swamps and marshes until early August, then it becomes less frequent. Usually it ceases about the middle of the month, sometimes a little before, but not unfrequently it continues later, and I have heard songs even so late as early September. About a month of silence now ensues; then the species comes again into voice. My record gives dates for the recommencement of singing from September 11 (?) and 18, to 28. The time of final cessation is carded into October—l5th and 17th are latest dates; but often the song is not heard after the first part of the month. In this supplementary season of song, singing is by no means general, and is usually confined to the early morning hours. But the birds seem more ambitious in their vocalism than earlier in the year. In the spring and summer the song is a simple monotone; in the autum this is often varied, and extended with accessory notes. A few preliminary chips, merging into a fine trill, introduce the run of notes which constitutes the usual song, which now terminates with a few slower, somewhat liquid tones. This seems to be the fullest attainment of the birds, and is often only partially or imperfectly rendered.

Behavior: T. S. Roberts (1936) points out the swamp sparrow “is more secretive in its habits than the Song Sparrow and is loath to leave the concealment of its retreats. It climbs up and down the coarse stems of the reeds and bushy shoots in a nimble, mouse-like manner and, when alarmed, descends into the dense marsh grass, runs rapidly away, and disappears for good and all. It rarely flies from the nest but slips quietly off and silently creeps away, keeping well under cover.”  The abrasive action of the coarse marsh grasses and sedges in which it lives keep the birds’ tail feathers continually worn.

It does much of its feeding by wading in shallow water like a sandpiper and picking insects and seeds from the surface. These activities are doubtless facilitated by its femur and tibiotarsus being proportionately longer than those of the song sparrow. Though E. T. Seton (1890) thought they showed great fear of getting wet, A. Allison (1904) describes them “splashing through the water like little muskrats.” S. D. Judd (1901) relates that a captive bird “showed an aversion to picking up seeds from its seed cup, preferring to take them from the surface of its drinking vessel.”

Except when migrating the swamp sparrow rarely flies more than a few dozen yards at a time, and rarely rises more than a few feet above the grass tops. In flight it pumps its tail rapidly up and down in a characteristic manner. Yet E. L. Poole (1938) shows that its wing-loading (ratio of wing area to body weight) of 4.30 square centimeters per gram is appreciably greater than the 3.94 square centimeters per gram in the larger congeneric song sparrow, which should make it an appreciably better flier.

Their behavior toward other species is little known. During fall migration they are often found flocking with other sparrows in dry fields. Yet on the wintering grounds in coastal Mississippi J. D. Corrington (1922) reports they “did not associate with other birds.” William Brewster (1937) relates that a Lincoln’s sparrow often drove swamp sparrows from a feeding plot in May.

While they do not trap as readily as some of their more granivorous relatives, swamp sparrows are not overly shy about repeating at bands ing stations. Over a 2-year period Marie A. Commons (1938) reports banding 104 individuals, 40 of which repeated a total of 162 times.

They enter traps with ground entrances more readily than those with top entrances.

Field marks: Adult birds are readily separable from other sparrows in the field by their dark, chunky aspect, their reddish cap and wings, clear gray breast, and white throat. Other aids to identification are the hard call notes that have the quality of cut-glass percussion, and the bird’s characteristic manner of pumping the tail in flight. Juvenile birds in summer are easily confused with young song sparrows and young Lincoln’s sparrows, for all have similar fine breast streakings, but as R. T. Peterson (1947) points out, the juvenal swamp sparrow is “usually darker on the back and redder on the wings.” In the hand the swamp sparrow’s smaller and more curving bill is diagnostic, as is its smaller size and, according to Olive P. Wetherbee (pers. com.), its softer texture to the touch.

Enemies: The main decimating factor of swamp sparrow populations on the breeding grounds are those related to changing water-levels, both natural and man-induced. While the creation of mill ponds and other bodies of water by artificial damming during the 19th century probably increased the range and density of the swamp sparrow within and beyond the glaciated areas of North America, the draining of morasses for housing developments is currently reducing its habitat markedly.

As the swamp sparrow usually nests just above the water level, a rise of only a few inches in that level can drown out every nest over wide areas. E. H. Eaton (1910) records that the birds had their nests thus flooded out in New York twice in 1906. I observed the same thing in Connecticut in 1956. Each year the birds take two or three of these 20-day gambles, that the waters will not rise until their young are fledged.

Herbert Friedmann (1963) states:

The swamp sparrow is generally an uncommon victim of the brown-headed cowbird. * * * Although the cowbird frequents marshes during migration, it tends to leave marsh nests alone. At Ithaca, New York, where both the swamp sparrow and the cowbird are common, there were no records of parasitism on the species.

* * * In Michigan, Berger (1951, p. 28) reported an unusual degree of parasitism on the swamp sparrow: he observed five nests, four of which had been victimized by the cowbird.

Although the swamp sparrow appears to be a rather uncommon victim of the brown-headed cowbird in most areas where the two exist together, it has been found to be a frequent and submissive host in southern Quebec. Here L. M. Terrill (1961, p. 10), between 1897 and 1956, found 322 nests of the swamp sparrow, of which 34, or roughly 10 percent, contained eggs of the cowbird. He wrote that the swamp sparrows in his area nested chiefly in sedgy tussocks among small willows in shallow water. Apparently this environment was more acceptable to the cowbirds than are the usual marshy areas.

The banding files show banded birds reported killed by: cats, dogs, hawks and owls, shrikes, rodents, cars, and weather conditions. Migratory cal amities such as the 1906 fall storm over Lake Huron (Lincoln, 1950) that killed many swamp sparrows must take their toll fairly regularly. E. G. Rowland (1925) described two individuals that succumbed to a “pea-green diarrhoea” (botulism?).

The Communicable Disease Center at Atlanta, Georgia, reports that the swamp sparrow has been found to carry antibodies of one or more of the American arthropod-borne encephalitides. The species has been found to be host to the following ectoparasites: four species of bird louse (Mallophaga): Degeeriella vulgate, Menacanthus chrysophasum, Philopterus subflavescens, and Ricinus sp.; three species of bird fly (Hippoboscidae): Ornithoica confluenta, Ornithomyja anchineuria, and Ornithomyia fringillina; and one tick, Haemaphysalis leporis-palustris.

Fall: As Cruikshank (1942) notes, the swamp sparrow on migration “regularly leaves the marshlands and occurs in all types of habitat with the exception of deep woodlands.” The crest of the autumn migration occurs throughout the northern states usually during the first week of October (Brewster, 1937 and Mason, 1938). The high percentage of immature birds in the population at this time attests the species’ high annual reproductive capacity. From his banding studies at Belchertown, Mass., E. G. Rowland (1925, 1928) concluded that local breeding birds disperse locally before September 19th, and most depart by September 23. Autumnal migrants average about a week’s stopover, as determined by repeat captures, and some individuals remained 2 weeks before moving on.

A swamp sparrow banded at Shirley, Mass., Oct. 4,1937 was shot the following January at Plant City, Fla. One banded at Branchpost, N.Y., Oct. 7, 1926, was found dead at Renfrew, Ont., May 2, 1928. Numerous returns to the same banding stations during successive spring and fall migrations suggest the birds retrace the same migration routes each year in both directions.

Winter: The species is a common winter resident in the Gulf States. In Georgia, T. D. Burleigh (1958) notes: “Its preference for the vicinity of open marshes and streams, however, limits its distribution, for rarely, if ever, will it be found in thickets or underbrush far from water. Cattail marshes are favored spots, and here its numbers during the winter months are limited only by the size of the area covered by the cattails. Bottomland fields overgrown with broom sedge likewise have their winter quota of Swamp Sparrows, provided a stream is close by and the ground is damp.” In Florida, A. H. Howell (1932) writes: “Swamp Sparrows are by no means confined to swamps in the winter season, but are found most frequently in fields overgrown with brush and briers, and particularly in patches of broom sedge where the ground is moist. The birds are silent at this season and quite inconspicuous as they feed on the ground, threading their way through the brush like mice.” In Louisiana, S. C. Arthur (1931) says “it is found not only in swamps but in old fields, overgrown with brush and briars, and particularly in wet patches of broom sedge. It leaves the salt-water tidal marshes, of course to the seaside sparrows.”

The uncommon but regular occurrence of a few swamp sparrows within the northern breeding range in winter may (Abbott, 1895) or may not (Bagg and Eliot) indicate that these individuals are nonmigratory. In Cambridge, Mass., William Brewster (1906) writes:

During the earlier years of my field experience Swamp Sparrows were not known to occur in midwinter near Cambridge, but on January 11, 1883, Mr. Charles R. Lamb met with a flock of seven birds in some dense maple woods on the western side of Pout Pond. Not long after this the cattail flags began to increase and spread in the Fresh Pond Swamps; since they became widely dispersed over the marshes lying to the north and west of the Glacialis, Swamp Sparrows have been constantly present there in winter. The birds vary considerately in numbers with different years, but one may be reasonably sure of starting at least three or four during a morning walk in December, January, or February, and under exceptionally favorable conditions as many as a dozen or fifteen may be seen.

Cruikshank (1942) says: “After the first killing frost in early November the Swamp Sparrow is purely casual in the highlands of the interior, but in the spring-fed marshes around New York City many regularly linger until Christmas, and some always remain to brave the winter.”

While no correlation is apparent between the number of such over-wintering birds and weather conditions, their survival probably depends largely on the comparative mildness of the season, or on their finding a suitable refuge with enough food and protection. Many individuals have repeated through the winter at banding stations on Cape Cod and Long Island. E. A. Mearns (1879) records a bird in the Hudson River Valley that remained through the severe winter of 1874-75  “* * * about a roadside drain, which, owing to a continual inflow of water, was not often frozen. The water was supplied through a small passing beneath the road, in which the bird doubtless found a desirable and effectual retreat in severe weather, as I several times started it from within the opening of this passageway, where the water was quite shallow.”

DISTRIBUTION

Range: Eastern South Dakota, northern Wisconsin, northern Michigan, southern Quebec, and Nova Scotia to southern Texas, the Gulf coast, and southern Florida.

Breeding range: The southern swamp sparrow breeds from eastern South Dakota (Yankton), central Minnesota, northern Wisconsin (Herbster, Outer Island), northern Michigan (Isle Royale), southern Ontario (Biscotasing, Eganville), southern Quebec (Kamouraska), northern New Brunswick (Miscou Island), Prince Edward Island, and Nova Scotia (Sydney) south to eastern Nebraska (Neligh), northern Missouri (St. Charles County), northern Illinois (Philo), northern Indiana (Crawfordsville, Richmond), south-central Ohio (Circleville), south-central West Virginia (Fayette and Greenbrier counties), western Maryland (Accident; Allegany County), southeastern Pennsylvania (intergrades with M. g. nigrescens; Delaware County), and southern New Jersey (intergrades; Salem, Cape May).

Winter range: Winters from eastern Nebraska, central Iowa (Sioux City), southern Wisconsin (Madison), southern Michigan (Grand Haven, Ann Arbor), southern Ontario (Toronto), central New York (Rochester, Schenectady), and Massachusetts (Danvers) south to southern Texas (Del Rio), southern Louisiana (New Orleans), southern Mississippi (Gulfport), southern Alabama (Petit Bois Island, Orange Beach), and southern Florida (Aucilla River, Cape Sable); casually north to New Brunswick (Sackville).

Casual records: Accidental in California (Niland) and Bermuda. Migration: (The data treat of the species as a whole.) Early dates of spring arrival are: Virginia: Blacksburg, March 21. West Virginia: Avalon, April 8. District of Columbia: March 9 (averages of 29 years, March 31). Maryland: Laurel, March 16. Pennsylvania : Meadville, March 23; State College, March 28 (average, April 15). New Jersey: Cape May, March 14. New York: Nassau County, March 23; Tompkins County, March 29. Connecticut: Portland, March 14. Rhode Island: Providence, March 10. New Hampshire: Concord, April 12; New Hampton, April 14 (median April 20). Maine: Bangor, March 20. Quebec: Montreal area, April 13 (median of 7 years, April 20). New Brunswick: St. John, April 6. Kentucky: Bowling Green, April 5. Illinois: Urbana, February 23 (median of 20 years, March 19); Chicago, February 26 (average of 16 years, March 27); Rantoul, March 5. Ohio: Buckeye Lake, March 17 (median of 40 years for central Ohio, April 1). Michigan: Battle Creek, March 23 (median of 34 years, April 6). Ontario: London, March 29. Iowa: Sioux City, April 12 (median of 38 years, May 1). Wisconsin: Madison, April 14. Minnesota: Minneapolis St. Paul, March 12 (average of 27 years for southern Minnesota, April 6). Oklahoma: Okmulgee and Tulsa counties, March 20. Nebraska: Neligh, March 24. South Dakota-Sioux Falls, April 23. North Dakota: Cass County, April 13 (average, April 19). Manitoba : Margaret, April 9; Treesbank, April 9 (average of 11 years, May 1). Saskatchewan: Davidson, April 23. Alberta: Glenevis, April 21. British Columbia: Tupper Creek, May 15.

Late dates of spring departure are: Florida: Tallahassee, May 15; Daytona Beach, May 9. Alabama: Florence and Birmingham, May 11. Georgia: Athens, May 20. South Carolina: Charleston, May 19 (median of 9 years, April 24). North Carolina: Asheville, May21; Raleigh, May 19 (average of 11 years, May 11). Virginia: Richmond, May 17. District of Columbia: May 27 (average of 42 years, May 11). Maryland: Laurel, May 26 (median of 6 years, May 21). Pennsylvania: Blair County, May 20. New Jersey: Cape May, May 14. Connecticut: New Haven, May 23. Massachusetts: Martha’s Vineyard, May 14 (median of 5 years, April 18). Louisiana: Baton Rouge, May 5. Mississippi: Bay St. Louis, May 4. Arkansas: Arkansas County, April 29. Tennessee: Knox County, May 7; Nashville, May 5 (median of 8 years, April 27). Kentucky: Bardstown, May 12. Missouri: St. Louis, May 15 (median of 13 years, May 6). Illinois: Chicago, May 31 (average of 16 years, May 27); Port Byron, May 24. Indiana: Wayne County, May 19 (median of 13 years, May 11). Ohio: central Ohio, May 30 (median of 40 years, May 16). Iowa: Sioux City, May 20. Wisconsin: Racine May 24. Texas: Cove, May 5; Sinton, April 28. Kansas: northeastern Kansas, MayO (median of 21 years, April 5). South Dakota: Vermilion, May 6. North Dakota: Cass County, May 25 (average, May 22). California: Salton Sea, May 9.

Early dates of fall arrival are: British Columbia: Vanderhoof, September 2. California: Daly City, October 21. Utah: Washington, October 23. Colorado: Mosca, October 2; San Luis Valley, October 23. Arizona: Bill Williams Delta, November 28. North Dakota: Jamestown, August 18; Cass County, September11 (average, September 15). South Dakota: Sioux Falls, September24; Yankton, October 10. Kansas: northeastern Kansas, September 24 (median of 21 years, October 1). Texas: Cove, October 13; Sinton, October 30. Wisconsin: Meridian, September 1. Iowa: Sioux City, September 25 (median of 38 years, October 5). Ohio: central Ohio, September 1 (median of 40 years, September 20). Indiana: Wayne County, September 23 (median of 9 years, September 30). Illinois: Glen Ellyn, September 2; Chicago, September 14 (average of 16 years, September 22). Missouri: St. Louis, September 25 (median of 13 years, October 2). Kentucky: Bowling Green, October 15. Tennessee-Knox County, September 26. Arkansas: Fayetteville, October 12. Mississippi: Rosedale, October 22 (mean of 19 years, October 24). Louisiana: Baton Rouge, October 10. New Hampshire: New Hampton, October 30. Massachusetts: Martha’s Vineyard, August 28 (median of 5 years, September 15). Connecticut: New Haven, September 16. New York: Tiana Beach, October 13. New Jersey: Cape May, September 21. Pennsylvania: State College, September 19. Maryland: Anne Arundel County, August 24; Laurel, September 18 (median of 6 years, September 24). District of Columbia: August 21 (average of 20 years, October 8). Virginia: Lexington, September 23. North Carolina: Asheville, October 2; Raleigh, October 10 (average of 11 years, October 21). South Carolina: Charleston, September 28 (median of 6 years, October 17). Georgia: Athens, October 2. Alabama: Fairfield, September 29; Livingston and Mobile Bay, October 6. Florida: Tallahassee, September 18; Chipley, October 4.

Late dates of fall departure are: British Columbia: Indianpoint Lake, October 9. California: near Riverside, November 13; near Keeler, November 1. Alberta: Glenevis, September 29. Saskatchewan: Yorkton, October 3. Manitoba: Treesbank, October 20 (average of 18 years, October 4). North Dakota: Cass County, October 28 (average, October 18). South Dakota: Aberdeen, November 5. Nebraska: Ravenna, October 28. Oklahoma: Norman, November 23. Minnesota: Minneapolis-St. Paul, October 26 (average of 8 years, October 23). Wisconsin: Delavan, November 3. Iowa: Sioux City, October 26. Ontario: Toronto, October 24. Michigan: Battle Creek, November 21 (median of 31 years, October 26). Ohio: central Ohio, November 13 (median of 40 years, November 4). Illinois: Chicago, December 6 (average of 16 years, October 31). Tennessee: Pulaski, November 4; Nashville, October 17 (median of 11 years, October 5). Prince Edward Island: Murray Harbour, October 26. New Brunswick: St. John, November 7. Quebec: Montreal, October 29 (median of 7 years, October 13). Maine: Lake Umbagog, October 31. New Hampshire: Concord, November 4. Rhode Island: Westerly, November 11. Connecticut: Portland, November 28. New York-Central Park, November 23; Monroe County, November 10. New Jersey-Cape May, November 26. Pennsylvania-State College, November 28. Maryland: Laurel, November 30. District of Columbia: -December 3 (average of 14 years, November 7). West Virginia: Bluefield, October 25. Virginia: Blacksburg, November 12.

Egg dates: Illinois: 25 records, May 9 to June 29, 16 records, May 26 to June 10.

Maine: 17 records, May21 to July 1; 10 records, June 8 to June 15.

Massachusetts: 36 records, May 9 to July 18; 18 records, May20 to June 3.

Michigan: 8 records, May 1 to June 25.

Minnesota: 11 records, May 18 to June 17.

New Brunswick: 5 records, May 27 to June 17.

Pennsylvania: 26 records, May 20 to June 20.

Wisconsin: 22 records, May 17 to June 20; 16 records, May 23 to May 20.

COASTAL PLAIN SWAMP SPARROW

MELOSPIZA GEORGIANA NIGRESCENS Bond and Stewart

Contibuted by DAVID KENNETH WETHERBEE

HABITS

This subspecies is similar to the nominate race but in breeding plumage according to G. M. Bond and R. E. Stewart (1951) the black streaking of the upper parts is distinctly heavier, especially on the nape and dorsal region; feather edgings of the upper parts, much grayer, less rufescent and buffy; tail and bill average darker; flanks, noticeably less buffy. In November specimens, the brown of their upper parts is somewhat richer and darker, and the light edgings of their dorsal feathers are considerably less distinct. This race is similar also to the pale form, M. g. ericrypta Oberholser but in both breeding and winter plumage, feather edgings of the upper parts are considerably narrower, not so whitish. General coloration of dorsal region is even darker than when compared with M. g. georgiana. Measurements based on a very small sample indicate that nigrescens may be slightly larger than the nominate race.

This race breeds in the Nanticoke River marshes, Wicomico County, across the river from Vienna, Md., and possibly also in other brackish tidal marshes where vegetation is suitable along the east shore of Chesapeake Bay in Maryland and Delaware.

DISTRIBUTION

Range: Southern New Jersey to eastern Maryland.

Breeding range: The coastal plain swamp sparrow breeds in tidal marshes of the Nanticoke River in southeastern Maryland and adjacent southwestern Delaware, and also around Delaware Bay (Delaware City and Bombay Hook, Delaware; Hancocks Bridge, Port Norris, and Delmont, New Jersey).

Winter range: Winters in the breeding range; also recorded on the Maryland coast (Ocean City), in east-central Virginia (Shirley), and once in the mountains of west-central Virginia (Lexington).

Egg dates: Maryland: 7 records, June 5 to June 22; 5 records, June 10 to June 15.