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Status: Population size: 2 million Photo by Mike Danzenbaker.

Thick-billed Kingbird
(Tyrannus crassirostris)

This big, raucous, aggressive flycatcher is a relative newcomer to the southwestern United States where it is sought by avid birders.

Identification
The Thick-billed Kingbird is a large flycatcher with a very large bill. It is dusky brown above, with a slightly darker head and a rarely-seen yellow crown patch. It has white underparts washed with pale gray on breast, pale yellow on the belly and under the tail. In fall, it may appear similar to Tropical Kingbird (Tyrannus melancholicus ), but has a darker crown and larger bill. Myiarchus flycatchers, in worn plumage, may look similar, but will show reddish in tail and wings without a darker head.

Distribution and Population Trends
First found in 1958 in Guadalupe Canyon on the Arizona/New Mexico border, this species has since become more widespread as a summering bird. However, in the United States it is still found mainly at a few places in Arizona. Occasionally it strays to southern California. In Mexico, its range extends far to the south through western Mexico and as far as Guatemala.

Ecology
This species breeds along permanent streams in lowlands and canyons, especially where large sycamores and cottonwoods grow. The nest is a large, loose open cup of twigs, grass, and plant down. The nest has a ragged look from beneath (the eggs may be visible from below). The species is aggressive in defense of it's nesting territory, attacking larger birds that come near the nest. The diet, though not well known, is probably mostly insects. The large bill size of this bird suggests the ability to feed on very large insects. It has been seen eating large beetles, cicadas, and others. It hunts from a perch, usually a high perch, but will forage low, especially in cold weather. It often calls upon returning to a perch after successfully catching an insect.

Threats
The small number of birds in the United States makes this species vulnerable to habitat degradation, especially of its preferred riparian habitats.

Conservation
Many of the areas where this species has been found in the U.S. are in public ownership. Protecting and restoring riparian habitats in these areas will be beneficial to the species as has been done along portions of the San Pedro River in southeast Arizona by installing fencing to prevent cattle from using the area. Research to determine more about this species' natural history would help conservation efforts. Almost nothing is known for sure about its status and ecology in Mexico and Central America.

What Can You Do?
Audubon's Important Bird Area program is a vital tool for the conservation of Thick-billed Kingbirds as well as other species. To learn more about the Important Bird Areas program and how you can help, visit: http://www.audubon.org/bird/iba/.

CIPAMEX, Audubon's BirdLife International partner in Mexico, has an Important Bird Areas program that is working to protect wintering habitat for Thick-billed Kingbirds and many other species. To learn more about Mexico's Important Bird Areas program and how you can help visit: http://132.248.79.80/wwwcampus/cipamex/

Information on where Thick-billed Kingbirds occur and in what numbers is vital to conserving the species. Help in monitoring this and other species by reporting your sightings to eBird. A project of Audubon and the Cornell Lab of Ornithology, eBird is the world's first comprehensive on-line bird monitoring program: http://www.audubon.org/bird/ebird/index.html.

References
Kaufman, Kenn. Lives of North American Birds. Boston: Houghton Mifflin, 1996.

National Geographic Society. Field Guide to the Birds of North America (3rd Ed.). Washington, D.C.: National Geographic Society, 1987.