Colima Warbler Life History

Habitat

Colima Warblers breed in chaparral and woodlands with oaks, pines, and grasses, between 1,500 and 3,200 meters (4,900–10,500 feet) elevation. They are most common on the north-facing slopes of mountains, in areas with shorter trees, taller shrubs and grasses, and deeper leaf litter. During the nonbreeding season, Colima Warblers occur in low vegetation in mountain forest, between 1,500 and 3,600 meters (4,900–11,800 feet) elevation.

Food

Colima Warblers feed mainly on insects and spiders. When these warblers first arrive in the Chisos Mountains in spring, oak trees have not yet leafed out, so the birds focus on extracting wasp eggs and larvae from oak galls. After trees and shrubs have leafed out and nestlings have hatched, Colima Warblers switch to capturing caterpillars and spiders. They hop between leaf clusters to pluck or glean insects and other small arthropods from leaves, twigs, and flowers. They also occasionally capture flying insects, take caterpillars from the ground, and feed on agave nectar.

Nesting

Nest Placement

The female builds the nest on the ground, typically under grasses, roots, rocks, and other structures that shade and conceal it.

Nest Description

An open cup composed of grasses, dead leaves, and bark. The inside is lined with grass, fur, or hair, and the outside sometimes contains moss or lichens.

Nesting Facts

Behavior

On their breeding grounds, Colima Warblers range from ground level up to the midstory of trees. On the nonbreeding grounds they generally remain in understory vegetation. Breeding birds are aggressive toward other Colima Warblers and some other species, such as Acorn Woodpecker, Ash-throated Flycatcher, Hutton’s Vireo, and Painted Redstart, but they sometimes join mixed-species flocks led by Black-crested Titmice. Nonbreeding birds generally occur alone or in small groups, though they occasionally join mixed-species flocks.

Based on studies in the Chisos Mountains, Colima Warblers are thought to be monogamous. The female builds the nest and incubates the eggs. Both adults feed the nestlings, which fledge after about 11 days.

Conservation

Partners in Flight estimates Colima Warbler’s global population size at 25,000 breeding individuals and rates the species a 16 out of 20 on the Continental Concern Score, indicating a Yellow Watch List species of high conservation concern.

Credits

Curson, J., D. Quinn, and D. Beadle (1994). Warblers of the Americas: an Identification Guide. Houghton Mifflin Company, New York, NY, USA.

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Dunn, J. L., and K. L. Garrett (1997). A Field Guide to the Warblers of North America. Houghton Mifflin Company, Boston, MA, USA.

Howell, S. N. G., and S. Webb (1995). A Guide to the Birds of Mexico and Northern Central America. Oxford University Press, Oxford, United Kingdom.

Lanning, D. V., J. T. Marshall and J. T. Shiflett. (1990). Range and habitat of the Colima Warbler. Wilson Bulletin 102:1-13.

Partners in Flight (2023). Avian Conservation Assessment Database, version 2023.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

Stephenson, T. and S. Whittle (2013). The Warbler Guide. Princeton University Press, New Jersey, USA.

Back to top