Wednesday, December 11, 2013
By HERB WILSON
Fee'-bee! Fee'-bee! You are probably hearing this buzzy song of the eastern phoebe in your neighborhood now. These flycatchers spend the winter in the southeastern United States and return to our area to breed. It's good to have them back.
The eastern phoebe likes to have several perches within its nesting territory. They find beetles delicious – also wasps, ants, grasshoppers and flies – and make doting parents.
Unlike most flycatchers that have a single, stereotyped song, eastern phoebe males sing a second song. The essence of the song can be captured as Fee'-b-be-bee. In both songs, the first note is exactly the same. For the Fee' bee song, the second note is raspy. The second portion of the Fee'-b-be-bee song is not as harsh and seems like stuttering.
Don Kroodsma found that eastern phoebe males alternate the two song types when they are singing at a high rate (about 40 songs/minute). At 25 songs per minute, only three of four songs are Fee'-bee songs. Males sing virtually only the Fee'-bee song if the singing rate falls below 20 songs per minute. The pattern is clear; the reasons for the pattern are unknown.
Eastern phoebes are easy to identify. They have the upright stance of flycatchers as they sit on their perches. The head is dark brown with dark eyes. Phoebes lack the conspicuous light eye-ring of many of our flycatchers. The upper parts of the body are olive brown, slightly lighter than the head. The wings have no wingbars. The throat is white and the rest of the underparts are a buffy-white. A distinctive behavior of eastern phoebes is their tail-wagging. The tail is rapidly flicked downward and then slowly raised to its original position.
Eastern phoebes like habitats that are only partly enclosed. Suburban yards, roadsides, stream banks and orchards are all good habitats. Within their nesting territories, phoebes have several perches that they habitually use. A phoebe will sit on its perch, looking for an insect in flight. When a potential meal is seen, the phoebe will sally forth and grab the insect in flight, returning to a perch.
These birds seem particularly fond of beetles, although wasps, ants, grasshoppers and flies are taken on the wing as well. Sometimes, millipedes and spiders may be taken from the ground.
Nests of eastern phoebes are cemented to a vertical surface and are made of an outer layer of mud and a softer, inner lining of grass and other soft materials. Before European settlement, eastern phoebes probably nested on cliffs and ledges. As Europeans colonized eastern North America, eastern phoebes easily adapted. They now readily nest on rafters and under the eaves of our houses and barns. In the 19th century, common names for the eastern phoebe were barn pewee and bridge pewee.
Phoebes will use the same nesting site from year to year, often building the new year's nest on top of the old one. Their faithfulness to a nesting site was first shown by John James Audubon, who tied some silver wire to the legs of nestling birds captured at their nesting site in Pennsylania. Sure enough, two birds returned to the same area the next year. Aubudon was apparently the first bird bander in North America!
Audubon's results were fortunate ones. Other biologists have shown that eastern phoebes are seldom faithful to the area where they were hatched and fledged (the natal site). In Indiana, none of 3,594 nestlings were found in the area in subsequent years.
Like most perching birds, adult eastern phoebes do show strong fidelity to a nesting site. Nearly 90 percent of pairs use the same nest site for second clutches. The fidelity from year to year is equally strong. Lots of other birds show similar behavior, with low natal site fidelity and high nesting site fidelity.
Eastern phoebes are industrious parents. It is normal for a pair to raise two broods in a summer. Each brood usually has five babies, although broods as high as eight have been reported. Unfortunately, phoebes are often the victims of female brown-headed cowbirds, which lay a cowbird egg in a phoebe nest, fooling the phoebes into raising a greedy cowbird chick along with their own chicks.
Data from the Breeding Bird Survey (begun in 1966) indicate that eastern phoebe populations are holding their own. The overall density of this species is highest in the New England states.
The species winters from Virginia to Texas and eastern Mexico. The center of the wintering population is in eastern Texas and the panhandle of Florida.
The replacement of square concrete culverts and small wooden bridges with circular, corrugated metal pipes has made such sites unusable for nesting. Biologists have discovered that flat nesting platforms placed in circular culverts are readily accepted as nest sites by eastern phoebes.
Herb Wilson teaches ornithology and other biology courses at Colby College. He welcomes reader comments and questions at:
Previous columns and other information on Maine birding can be found at his blog: