Northern Rough-winged Swallow | Life Histories of North American Birds | A.C. Bent
Feather Pic Arthur Cleveland Bent

Life Histories of Familiar North American Birds
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Northern Rough-winged Swallow
Stelgidopteryx serripennis [Rough-winged Swallow]

Contributed by Edward von Siebold Dingle
[Published in 1942: Smithsonian Institution United States National Museum Bulletin 179: 424-433]

The rough-winged swallow was discovered by John James Audubon in Louisiana, but the description of the bird in his "Ornithological Biography" is based rather on specimens collected many years later at Charleston, S. C., which city is, therefore, the type locality. Audubon's (1838) description of his first meeting with this swallow is as follows:

On the afternoon of the 20th of October 1819, I was walking along the shores of a
 forest-margined lake, a few miles from Bayou Sara, in pursuit of some Ibises, when I observed a flock of small Swallows bearing so great a resemblance to our common Sand Martin, that I at first paid little attention to them. The Ibises proving too wild to be approached, I relinquished the pursuit, and being fatigued by a long day's exertion, I leaned against a tree, and gazed on the Swallows, wishing that I could travel with as much ease and rapidity as they, and thus return to my family as readily as they could to their winter quarters. How it happened I cannot now recollect, but I thought of shooting some of them, perhaps to see how expert I might prove on other occasions. Off went a shot, and down came one of the birds, which my dog brought to me between his lips. Another, a third, a fourth, and at last a fifth were procured. The ever continuing desire of comparing one bird with another led me to take them up. I thought them rather large, and therefore placed them in my bag, and proceeded slowly toward the plantation of William Perry, Esq., with whom I had for a time taken up my residence.

The naturalist examined his specimens carefully and saw that they were different birds from the sand martin, or bank swallow, but he continues. "At this time my observations went no further."

Then, "about two years ago, my friend the Rev. John Bachman, sent me four Swallow's eggs accompanied with a letter, in which was the following notice--'Two pairs of Swallows resembling the Sand Martin, have built their nests for two years in succession in the walls of an unfinished brick house at Charleston, in the holes where the scaffolding had been placed. It is believed here that there are two species of these birds.' . . .

"I have now in my possession one pair of these Swallows procured by myself in South Carolina during my last visit to that State."

The roughwing enjoys a very extended range in the Western Hemisphere. Essentially a bird of the Austral Zone, it does not hesitate to establish itself in mountainous country thousands of feet above sea level. According to Miller (1930) the bird breeds in the heart of the Pocono Mountains of Pennsylvania, at about 2,000 feet; in western North Carolina Brewster (1886) found it up to 2,500 feet. James B. Dixon says that in California it breeds from sea level up to 6,500 feet. Grinnell, Dixon, and Linsdale (1930) report specimens collected at Red Rock P. O., Calif., at an elevation of 5,300 feet; also, birds observed at Petes Valley, 4,500 feet; Secret Valley, 4,500 feet; and Jones, 5,400 feet.

This bird, also locally known as the sand, or gully, martin, is rather solitary in habits and usually does not congregate during the breeding season, as does its near relative the bank swallow. However, as Dawson (1923) says, "favorable conditions may attract several pairs to a given spot, as a gravel pit, but when together they are little given to community functions."

Courtship.--Grinnell and Storer (1924) write: "From time to time the males were seen in pursuit of the females and, while so engaged, to make rather striking use of their seemingly plain garb. They would spread the long white feathers (under tail coverts) at the lower base of the tail until they curled up along either side of the otherwise brownish tail. The effect produced was of white outer tail feathers, such as those of the junco or pipit. Males can by means of this trick be distinguished from the females at a distance of fully 50 yards. An examination of specimens in hand reveals the fact that the under tail coverts of the males are broader and longer than those of the females."

Nesting.--Burrows, excavated in precipitous banks of clay, sand, or gravel by the birds themselves, are the usual nesting sites of the roughwing. The length of the burrow depends, as H. H. Bailey (1913) says, "much on the character of the soil in which it is started. Weather conditions also make a moist or hard soil for them to work in." Minimum depth of burrow is about 9 inches; and, in these shallow excavations, the nest can be sometimes seen from the outside. The greater number of tunnels, however, are long enough to keep the nest from view and protect it from driving rains. Under ideal working conditions, tunnels 4 and 5 feet long are often excavated, sometimes reaching even a distance of 6 feet.

Bailey further says: "The height of the nesting cavity in the bank also varies greatly, the nature of the soil strata affecting the drilling of the hole, which is made by the birds using their feet to scratch with, and push the dirt backward out of the tunnel. Unlike the kingfisher, their beaks play a secondary part in the drilling of their home, so they usually select a place in the soft strata where the roof will be the under side of a hard strata of soil, and so eliminate the chances of a cave-in.

Dawson (1923) writes that "in open country, where the cover is scarce but the food supply attractive" he found them nesting "along irrigating ditches with banks not over two feet high." Weydemeyer (1933) found nests in Montana in banks 1 to 50 feet up.

This swallow is an excellent example of a species that can readily adapt itself to conditions and utilize any kind of cavity for the reception of its nest. It builds in holes in masonry, sides of wooden buildings, adobe walls, quarries and caves; crannies and ledges under bridges, culverts, and wharfs; and gutters, drainpipes, and sewerpipes. Deserted burrows of the kingfisher (Megaceryle alcyon) also are frequently used, and in the West holes of ground squirrels and other small mammals. According to Tyler (1913), these holes are thoroughly renovated before occupancy "as is evidenced by the small mounds of dust, leaves and trash that are to be seen below the entrances to occupied cavities."

A nesting site near the village of Mount Pleasant, S. C., used occasionally by rough-winged swallows was in the end of a hole in a bank of burnt oyster shell--location of an antebellum lime kiln facing Copahee Sound. A round piece of wood had been buried in the lime, and when it decayed it left a tunnel 3 inches wide and several feet deep. The late Arthur T. Wayne first showed it to me. He related that, on one occasion, upon his approach, the bird left the hole and was immediately pursued closely by a sharp-shinned hawk (Accipiter velox). It eluded its pursuer, however, and dived back into the hole, where it remained.

Howell (1924) writes: "A most remarkable site selected by one or more pairs of these birds for their nest was on a buttress beneath the deck of a transfer steamboat which made daily trips on the Tennessee River from Guntersville to Hobbs Island, a distance of 24 miles, leaving at 10 a.m. and returning at 6:00 p.m. The birds, of course, followed the boat all the way to feed their young. A nest examined on the boat June 19, 1913, contained young."

Hollow trees, it seems, are rarely used, but Eifrig (1919) says: "June 10, 1915, I saw a pair. . . nesting in a dead cottonwood on the top of a dune at Millers. . . . The female looked out of the hole and the male perched as close by as he could." Observers agree that the entrance hole of the roughwing's tunnel differs from that of the bank swallow; S. F. Rathbun says: "Quickly I detected the difference that existed in the shape of the entrance of the nesting tunnel used by the rough-winged swallow, by contrast with that of the bank swallow; for in the case of the former the shape of the entrance was elliptical, sometimes much so; it was larger and appeared carelessly made. But the bank swallow would make the entrance more circular, especially if the digging was easy; it was decidedly smaller, neater in its outline. And a person could readily see these differences even when some distance from the bank."

Most of the birds that nest in cavities, tunnels, or crevices build either no nest at all or one of indifferent construction; the roughwinged swallow is no exception. S. S. Dickey's description of the nests as "loose, crude foundations" is a good one.

The bulk of the nest depends largely on the size of the cavity that holds it. Nests I have taken from sand banks along the South Carolina coast are 1 1/2 to 1 3/4 inches thick and are composed of grasses and rootlets.

A nest collected by J. F. Freeman from a timber under a wharf, where there was plenty of room, is a rather bulky affair, built on a foundation of large chips and pieces of bark deposited during construction of the wharf. The nest proper is made of grasses and a few leaves of live oak (Quercus virginiana) and is lined with fine grasses. The distance from the top of the nest to the beam is 5 inches.

According to locality various materials are used, as grasses, pine needles, straw, weeds, roots, and, as Dickey says, "shells of chicken eggs and now and then bud scales, panicles, seed tops, petals of such flowers as dogwood (Cornus florida), Carices, and Juncus. Into their composition go pieces of deciduous leaves and petioles, notably those of the black willow (Salix nigra) and heart leaf willow (Salix cordata). A number of nests curiously contained moist horse dung; we wonder why. Perhaps the vile smell tends to ward off vermin."

R. F. Mason, Jr., reports the wide use of holly leaves in Maryland. In coastal Virginia H. H. Bailey says that seaweed is largely used in nest construction.

In Florida, according to Howell (1932), nests are made of dried rootlets, grass, weed stems, and a few dried beans and are lined with dried or partly burnt grass.

Dickey writes: "Curiously, the parents supply broods daily with beds of fresh green leaves of the common locust (Robinia pseudoacacia). Soiled leaves are removed, with the dung."

A departure from the usual type of nest construction is described by Goss (1886), who says: "Nest in holes in banks of streams, constructed of the same material as the Barn Swallow." He describes the nest of the latter bird as "constructed of layers of mud and grasses, and lined with fine grasses and downy feathers."

"In the vicinity of Fortine, Mont.," says Weydemeyer (1933), "I have been able to determine the stage of nesting, at some time during the season, shown by thirty-four nests of the Rough-winged Swallow. . . . I give below the range of dates, for different stages of nesting, which these records show. Nest under construction: May 8, 1931, to June 15, 1929. Eggs (seven nests), June 14, 1928, to July 6, 1923."

Eggs.--[AUTHOR'S NOTE: The rough-winged swallow lays anywhere from four to eight eggs to a set, but the set usually consists of six or seven eggs; thus the sets will average larger than those laid by the bank swallow. They are more elongated, as a rule, than the eggs of other swallows, usually elliptical-ovate. They are somewhat glossy, pure white, and unmarked.

The measurements of 50 eggs average 18.3 by 13.2 millimeters; the eggs showing the four extremes measure 20.6 by 14.7, 17.3 by 15.0, 16.5 by 12.7, and 17.8 by 12.2 millimeters.]

Young.--A. F. Skutch says that the female incubates the eggs for 16 days, while Dickey gives 12 days. Apparently the male occasionally helps his mate with incubation duties, and Blake (1907) mentions a nest under his observation in Vermont where the birds took turns at sitting on the eggs.

Dickey says: "The young at first are mere weak infants, gray and yellow, with the blood vessels and organs showing somewhat through their skins. They are coated with streaks of gray down. They develop rapidly. Within one week they assume somewhat the aspect and plumage of the adults. When they are ready to leave the nest, at the lapse of 12 days, they are pale brown but cannot well be differentiated from the adults while on the wing. I went to the trouble to collect and examine young just out of the nests. Superficially their forms seemed more like bank swallows than like their adult parents."

Skutch continues: "When 13 days old the nestlings were well feathered, but they remained in the burrow a full week longer, gaining strength to fly." Thus, he considers the nestling period to be 20 or 21 days. Weydemeyer (1933), out of a total of 34 nests under observation, gives the following dates of young in nest: June 8, 1921, to July 9, 1928. In nine other nests, the young left the nest by July 22, 1931, to July 29, 1930.

The roughwing raises one brood during the season.

Plumages.--At the time of leaving the nest the young birds are similar to their parents in size, feathering, and length of wing and tail, but the first primary lacks the roughness of the adult feather; indeed, it is probable that nearly a year passes before the young birds acquire this saw edge that gives them their name. Also, the plumage is tinged with rufous or cinnamon, especially on the throat and upper breast; the wing coverts and tertials are margined with the same ruddy tint.

Dwight (1900) says: "First winter plumage acquired by a complete postjuvenal moult after the birds have migrated southward in September, or very likely while they move leisurely along in flocks."

The first nuptial plumage is apparently acquired by wear. Adults have a complete postnuptial molt after they have migrated southward, mainly in September or later. The sexes are alike in all plumages.

Food.--Howell (1924) says: "The food of the rough-winged swallow consists principally of insects, with a few spiders. Flies composed nearly one-third (32.89 per cent) of the total. Ants and other Hymenoptera are extensively eaten, and bugs to a lesser extent. Beetles amounted to nearly 15 per cent of the food and included the cotton-boll weevil, alfalfa weevil, rice weevils and flea beetles. A few moths, caterpillars, dragonflies, Mayflies, and an occasional grasshopper make up the remainder of this bird's food."

Behavior.--In the field the roughwing appears as a sober-colored little bird, plain grayish brown above and lighter below. At a distance it can easily be confused with the bank swallow, but when the latter bird sweeps over the observer the breast band is readily detected. If the two birds are seen together, the larger size of serripennis and its more brownish appearance are at once apparent.

Lynds Jones (1912) says: "The more deliberate flight of the Rough Wing as compared with the Bank was always noticeable. The flight also tended to be more straight-away, with fewer abrupt turnings. The Rough-Wing gives one the feeling of great reserves of energy."

Theed Pearse mentions that the "flight differs from other species of swallow, stroke of wing being higher."

When its nest is approached the bird glides out and is soon joined by its mate; then the two usually wheel back and forth at a short distance away. If bare branches or telegraph wires happen to be near at hand the birds will perch upon them and wait for the intruder to go.

Dickey writes that the "parent, not seemingly uneasy, tended to hover half-concealed behind a screen of black willows, 200 feet away. It would, however, glide out, to see what was taking place, then disappear. In describing a pair of breeding swallows, Brewster (1907) writes: "Once they alighted on a large, flat-topped boulder at the water's edge where they moved about by a succession of short, quick runs, reminding me of Semipalmated Plover feeding on a sand beach. I have never before seen Swallows of any kind move so quickly by the aid of their feet alone."

Henshaw (1875) says that on the Provo River, Utah, "they roost in large numbers upon the dead bushes along the banks. So numerous are they and so closely do they sit huddled together that six individuals were secured at a single shot."

Voice.--The roughwing is, generally speaking, a silent bird; its notes, rather weak and inaudible at a distance, are described as "harsh" or "squeaky" by observers.

Dickey writes: "They give vent to a kind of rasping squeak, difficult to describe in mere words. The exclamations are vented while the species glides upstream or when it is approached near the nest; quiz-z-z-zeep; quiz-z-z-zeep is what it sounds like." Cooper (1870) writes: "They have only a faint twittering note when flying."

Grinnell, Dixon, and Linsdale (1930) refer to the call of the roughwing as "their sputtery notes, pssrt, pssrt."

Enemies.--The rough-winged swallow does not appear to be greatly victimized by predatory birds and mammals; strong powers of flight, more or less inaccessible nesting sites, and generally solitary habits combine to keep it out of danger.

H. H. Bailey (1913) says: "The mortality in this section is great, their chief enemy being the black snake."

Probably the greatest cause of destruction to eggs and young is the flooding of the burrows by spring tides and river freshets. According to Wayne (1910) this condition is quite prevalent in the flat, sandy coastal country of the Southeast. It also often happens elsewhere, owing to the fact that, while this swallow usually burrows near the top of the bank, it often excavates nearer the base. In building under bridges and culverts the bird sometimes places its nest so near the water that even a slight rise would engulf it. Dickey says: "From potholes in sandstone cliffs near Worely, Monongalia County, W. Va., I have known anglers to extract the young of rough-winged swallows. These, they contended, proved to be excellent bait in bass fishing in local creeks."

Peters (1936) lists specimens of this swallow from Maryland and Virginia as being found infected with the mites Liponyssus sylviarum and Atricholaelaps sp.

Without positive proof I believe that the common sand crab (Ocypode albicans) might, to a limited extent, prey on eggs and nestlings of the roughwing. This crustacean abounds on the south Atlantic coast, excavating its burrows in sand hills and the bases of sand banks, as do the swallows. It causes much damage by burrowing into turtle nests on the Carolina coast and consuming the eggs. It is ever on the alert for anything edible that the waves might bring ashore. Terns and shearwaters washed up after hurricanes are quickly ruined as specimens, as I have several times sorrowfully experienced.

Winter.--While this swallow is highly migratory and the great majority of individuals winter south of the United States, records from five states designate it as a winter visitant within our borders. It is possible that some of the so-called spring arrivals are birds that have wintered in the neighborhood. Wayne (1910) says: "The birds of this species which winter along the coast, generally, if not invariably, confine themselves to large bodies of water adjacent to wooded lands."

Griscom (1932) says that "the Rough-winged Swallow is a common winter visitor to the whole of Guatemala, except the Pacific coast." He quotes from Mr. Anthony's notes as follows: "Common during the winter months to about 8000 feet altitude. The first were noted at Progreso about September 8, with mixed flocks of Cliff and Barn Swallows. A considerable flight of these species appeared at this station on the above date and hundreds were seen along the telegraph wires for a day or two, when they became much less common but not rare until the following May. In the altitudes, Stelgidopteryx is apt to be seen with Tachycineta which is equally common."

Northern Rough-winged Swallow* Stelgidopteryx serripennis [Rough-winged Swallow]

*Original Source: Bent, Arthur Cleveland. 1942. Smithsonian Institution United States National Museum Bulletin 179: 424-433. United States Government Printing Office