Author: Caitlyn Gillespie

Bird Bio: Acorn Woodpecker
By Ellie Armstrong, KBO Research and Monitoring Intern

The Acorn Woodpecker (Melanerpes formicivorus) is common year-round in oak woodlands near the West Coast. Oregon was believed to hold the most northerly population of this species until a colony was discovered in Washington in 1989. Considered clown-faced in appearance, the Acorn Woodpecker’s distinctive “waka-waka” call can often be heard whenever oak trees are near. Male and females look similar, although males can be distinguished by the presence of more red on the top of their heads.

There are several morphological adaptations shared by woodpeckers. One of these is the zygodactyl foot. While many birds have three toespointing forward and one backwards on each foot, woodpeckers have two toes pointing forwards and two pointing backwards; this arrangement allows woodpeckers to cling securely to the sides of trees. They also have extremely long, sticky, and barbed tongues that help them probe crevices and collect insects. Their tongues wrap completely around their skulls and can extend out as far as 5 inches. To accommodate a lifestyle of drumming on wood, the bone at the base of their bill is porous and acts as a shock absorber.

Acorn Woodpeckers are communal breeders, a characteristic shared by only three percent of all bird species. Up to as many as 15 individuals from multiple generations will live together in an established territory. Only some of these individuals breed, while others help raise the young. The number of breeding individuals varies, but usually consists of one or two females and up to four males per female. An Acorn Woodpecker group will excavate several large cavities in dead or live trees; one cavity is typically used for the nest and the remaining cavities are used for roosting.

Acorns and insects comprise the bulk of the Acorn Woodpecker diet. The woodpeckers collect acorns during autumn and winter and store them in dead trees and telephone poles and other manmade structures, including the siding of houses. These acorn storage sites are called granaries, and one granary may contain as many as 50,000 acorns. All of the woodpeckers that live in a community are responsible for collecting and storing acorns. Old granaries are used year after year, but new ones are made as well.

This article appears in KBO’s 2013 Winter Newsletter.

References:

Ehrlich, Paul, David Dobkin, and Darryl Wheye. The Birder’s Hnadbook. New York: Simon & Schuster Inc., 1988. 283-285. Koenig, Walter, Peter Stacey, Mark Stanback, and Ronald Mumme. “Acorn Woodpecker.” Birds of North America. 194. (1995)

Marshall, David B. et al, eds. Birds of Oregon: A General Reference. Corvallis: Oregon State University Press, 2003.;

Sibley, David. The Sibley Guide to Bird Life and Behavior. New York : Alfred A Knopf, Inc. , 2001.

By: Teresa “Bird” Wicks, KBO Education Intern

The Black Phoebe (Sayornis nigricans) is the only black and white flycatcher found in North America. Thus, they are easily distinguished by their mostly black body and white belly. Eastern Kingbirds and Eastern Phoebes, similarly, are dark above and pale below, but are generally grayer and also have a pale throat and breast. Additionally, the range of the Black Phoebe barely overlaps the ranges of these two species. The range of the Say’s Phoebe, however, does overlap that of the Black Phoebe, but the gray-brown upper parts and rust-colored belly of the Say’s Phoebe make it difficult to mistake for a Black Phoebe. When Black Phoebes are perched they are often seen “wagging” their tails, a characteristic shared by both the Say’s and Eastern Phoebes.

The Black Phoebe’s range extends north from western South America through most of Central America and Mexico, and into the United States. In the United States, they are predominantly found in the southwestern states, historically breeding and wintering along western California into the Rogue Valley in Oregon. In the late 20th century, the Black Phoebe’s range expanded north to Curry County, where they are now considered year-round residents, and Coos County, where winter sightings are becoming more common. Due to their ability to cohabitate with humans, the Black Phoebe’s range continues to expand in Oregon, with irregular reports in the Umpqua and Willamette Valleys.

As with other flycatchers, Black Phoebes are primarily insectivorous. They feed by sallying from their perch and catching airborne insects, or by gleaning insects from plants. Small insects are consumed on the wing, while larger insects are carried back to a perch where they can be killed and then consumed. Occasionally, Black Phoebes will dive into the water to capture minnows and other small fish!

Black Phoebes are most often found along streams, ponds and marshes, typically perched on the lower branches of riparian trees or low-lying manmade structures. When it comes to nesting, male Black Phoebes hover near potential nest sites whereas females choose the final site and construct the nest. Their open-cup nests, made of mud and vegetation, are cemented to cliff faces, bridges, and other manmade structures, and resemble Barn Swallow nests.

This article appears in the Winter/Spring 2013 Newsletter. 

Sources: Marshall, D.B., M.G. Hunter, and A.L. Contreras, Eds. 2003. Birds of Oregon: A General Reference. Oregon State University Press, Corvallis, OR. 768 Pp.; Wolf, B.O. 1997. Black Phoebe (Sayornis nigricans). In The Birds of North America, No. 268 (A. Poole and F. Gill, eds). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists’ Union, Washington, D.C.
The Black Phoebe is a nearly all black bird with a white belly. Photo © Jim Livaudais 2013.