ID: brown swallows

A family of Northern Rough-winged Swallows, 19 July 2011, Forest Grove, Oregon by Greg Gillson.

The identification of swallows is generally considered a "beginning birder's" identification problem. As Kenn Kaufman explained in Advanced Birding, it is not so much that swallows are misidentified, rather many swallows go unidentified as they fly by overhead twisting and turning, swooping and diving. As an eBird reviewer, however, I think that some misidentification is happening with swallows--and not just by beginners, either. The ID problem I want to highlight is the 3 brown swallows. Yes, three. Northern Rough-winged, Bank, and Tree swallows. Wait--Tree Swallows? Yes indeed!

You see, the first set of juvenile feathers on Tree Swallows are brown. Then these 3 or 4 month old swallows go through another complete "preformative" molt in fall--basically into an adult-like plumage. However, many of the first-year females have a dull brown plumage. They keep these feathers until the next autumn, so some first-year females arrive on the breeding grounds in spring a rather drab brown color. Thus, at any time of year you may encounter brown Tree Swallows. 

Northern Rough-winged Swallow
Rather evenly brown above. The throat and upper chest are pale brownish merging into white belly. Long winged and graceful languid flight. Call is a rough flatulent-like sound "pbbbt." Nest in single or small groups of burrows in sandy or muddy bank.

Northern Rough-winged Swallow, 9 August 2010, Forest Grove, Oregon by Greg Gillson.

Bank Swallow
Brown back with contrastingly darker wings. Underparts, including throat, white. Dark, full brown neck collar, sometimes with a central "spike" going down the belly. A small swallow; wings shorter and more triangular. Flight more direct with rapid wing beats. Call is a rough buzz like electric line, "bzzzt," or "prit-prit." Nest in large colonies of burrows in sandy bank or cliff.

Bank Swallow, 29 May 2013, Malheur NWR, Oregon by Greg Gillson

Bank Swallow, 28 May 2013, Hines, Oregon by Greg Gillson.

Tree Swallow
Adult males have metallic steel-blue back and wing coverts, black mask, gleaming white underparts. Females are duller. Some first-year females are brownish rather than blue, but usually have some blue feathers on the bend of the wing, at least. Juveniles are brownish with white throat and an indistinct (usually) grayish breast band. In flight the breast band can be conspicuous, but not as strong as Bank Swallows. Rather long wings and graceful flight. Calls are a liquid twittering. Nest in tree cavity or nest box.

Tree Swallow, juvenile showing Bank Swallow-like breast band, 10 July 2013, Hillsboro, Oregon by Greg Gillson.

Tree Swallow, first year female, 17 April 2004, Forest Grove, Oregon by Greg Gillson.

Tree Swallow, male, 16 April 2010, Forest Grove, Oregon by Greg Gillson.

In 2008 Don Roberson wrote an article, Identification of brown swallows, on his Monterrey, California birding pages that provides additional ID tips.

Telling Swallows from Swifts

Tree Swallow, Beaverton, Oregon, 18 May 2011 by Greg Gillson.

Many beginning birders struggle to differentiate swallows from swifts. Even separating the different swallows from each other is one of the first identification challenges a beginning birder faces. No doubt part of it is that both swallows and swifts are most-frequently seen darting rapidly through the air, backlit against the sky. If you can't follow them or even find them in your binoculars, how are you to identify them and see those subtle field marks?

As Kenn Kaufman says, in his new Field Guide to Advanced Birding (2011), it's not so much that swallows are misidentified, but "simply left unidentified."

But, then, how do some birders identify them nearly instantly as they fly high overhead, not even using binoculars? They differ subtly in behavior, habitat and niche, seasonality, and voice. Structurally, the wing bones are different so that the flight styles are notably different. Specifically, swallows flap more slowly and swoop gracefully, while swifts have more direct flight with rapid wing beats and brief glides.

Swallows

Behavior
Swallows are often seen flying through the air darting after insects, or seen sitting on wires.

Habitat and niche
Most swallows are usually found over open country or water. They can feed low to the ground or quite high in the sky, sometimes over cities or forests. They frequently perch on telephone wires, bare tree branches, fence lines. Most are cavity nesters in trees, nest boxes, cliffs, or banks, some creating enclosed mud nests on cliffs, barns, or porches.

Flight style
Feeding flight consists of graceful glides, banking, and turns interspersed irregularly with snappy, irregular deep flapping on flexible, broad-based, pointed wings. Commuting flight is more direct, interspersing several flaps with short pauses or brief glides with wings partially open (or nearly folded so that the tips of the wing are back near the tail).

Shape
Swallows have very short necks and very short, broad bills. They have rather short tails--look at the photo of the flying swallow below and note that the white undertail coverts (body feathers) come nearly to the end of the tail. Swallows have pointed wings. Look how far the flight feathers extend past the rump in the photo above. But notice that it is only the the outer part of the wing that is long. The inner arm part of the wing is exceedingly short compared to the outer "hand" portion of the wing--look how close the wrist is to the body! The base of the wing is quite wide, creating rather triangular shaped wings in flight.

Seasonality
In the Pacific NW, swallows are present in good numbers primarily from late March to early October, with some species arriving earlier (late January), with stragglers occasionally seen through the winter west of the Cascades.

Voice
Swallows have various chirping and grating calls, strung together into "songs" that can't be considered very musical!

Tree Swallow, Forest Grove, Oregon, 6 July 2007 by Greg Gillson.

Swifts

Behavior
Swifts are almost only seen flying through the air darting after insects. They have weak feet and are not able to perch on wires or tree limbs.

Habitat and niche
Depending upon species, swifts are found over open country, towns,  forests, or cliffs. They usually fly quite high in the sky. They fly into and cling to the insides of chimneys, cracks in cliffs, or hollow trees. During migration thousands may converge at dusk to roost for the night in old stone chimneys at favored locations.

Flight style
Direct flight with rapid wing beats interspersed with occasional set-winged glides.

Vaux's Swift, Forest Grove, Oregon, 22 September 2009 by Greg Gillson.

Shape
The arm bones of swifts are so short that only the outer hand is present--very much like the wing of a hummingbird. Flight is thus twinkling with rapid wing beats on stiff, narrow pointed wings. The tail on Vaux's swifts are short to nearly absent; others have forked tails.

Seasonality
In the Pacific NW, swifts are present from mid-April to early October.

Voice
Swifts have squeaky, chipping calls.

Vaux's Swift, Hillsboro, Oregon, 3 August 2008 by Greg Gillson.

Range in the Pacific Northwest

The following are the locations where swifts and swallows are most often encountered in the Pacific Northwest.

Tree Swallows are abundant over ponds. They use nest boxes placed very near water.

Violet-green Swallows are found in town and over forested lands. They nest in holes under eaves or nest boxes in yards.

Barn Swallows are found in country and towns, nesting in open barns and sheds.

Cliff Swallows nest under barn eaves and cliffs.

Banks Swallows nest in colonies in river banks. They are rather rare west of the Cascades.

Northern Rough-winged Swallows nest in river banks.

Purple Martins are rather rare and local in the Pacific Northwest, along the coast, Columbia River, and mountains.

Vaux's Swifts are regular over towns and forests.

White-throated Swifts are local over cliffs and rimrock in the Great Basin.

Black Swifts are rare in mountains.

At the pond... Tree Swallow

Tree Swallow, Fernhill Wetlands, Forest Grove, Oregon on 12 April 2008 by Greg Gillson.

 

The Tree Swallow is generally the first swallow to arrive in the Pacific Northwest in spring. In fact, in northern California it regularly winters in small numbers in the Central Valley and along the coast. West of the Cascades in Oregon and Washington it arrives in late January. Additional birds arrive throughout the Pacific NW through March and into April, when they can be found over many ponds hawking insects and inspecting nest boxes placed there for them or inspecting holes in trees over water for suitable natural nest sites. Most migrate south from August to October, but there are some mid winter reports in the Pacific NW, primarily along the coast.

Tree Swallows are widespread across North America. In summer they occur from the edge of the treeless tundra in Alaska and across northern Canada south to just the northern edge of southern California, Arizona, New Mexico, Texas and the Gulf States. In winter, as discussed, they occur along both US coastlines from Virginia to Florida to Texas, and southern California and along the Colorado River in Arizona, and from there south throughout Mexico to Guatemala, Honduras, and also in Cuba.

The Tree Swallow is a metalic blue above with blackish-brown wing and tail feathers and white underparts. They show a black mask. Females are duller than males. Juveniles and first year birds can appear quite brownish, but show the darker mask. The photo above shows an adult male in brilliant breeding plumage.

A similar bird in the West is the Violet-green Swallow. The back of Violet-green Swallow, seen at close range, is a shocking bright lime green. The side of the face is white (lacking the black mask surrounding the eye that Tree Swallow shows). In flight, the Violet-green Swallow has shorter, more triangular wings, and white rump patches that almost meet at the base of the upperside of the tail. Violet-green Swallows are much more likely to make their home in nest boxes in your backyard than Tree Swallows--unless you live right on the water.

Juveniles and dull first year birds might be mistaken for Bank or Rough-winged Swallows. Indeed, some Tree Swallows show a hint of dusky breast band. But the dark, well-defined mask is a primary clue to identification if well seen. Bank and Rough-winged Swallows do not nest in nest boxes, so any brownish swallows doing so are likely Tree (or Violet-green) Swallows.