Bird GuideWood WarblersColima Warbler

At a Glance

In our area, this Mexican species occurs only in Big Bend National Park in western Texas. There it is fairly common in summer at upper elevations in the Chisos Mountains, but seeing it requires a day-long hike or a lengthy horseback ride. The Colima is larger than most warblers and tends to be sluggish, foraging deliberately in the dense undergrowth or in the lower levels of the oaks.
Category
Perching Birds, Wood Warblers
Conservation
Low Concern
Habitat
Forests and Woodlands, Shrublands, Savannas, and Thickets
Region
Texas
Behavior
Direct Flight, Flitter, Rapid Wingbeats
Population
25.000

Range & Identification

Migration & Range Maps

Only a short-distance migrant, wintering in southwestern Mexico. In Texas, arrives in April and departs mostly in August and early September.

Description

5" (13 cm). Gray, with white eye-ring and yellow undertail coverts. Virginia's Warbler (migrant through Big Bend) is smaller, lacks strong brown wash on sides.
Size
About the size of a Robin, About the size of a Sparrow
Color
Brown, Gray, Green, White
Wing Shape
Rounded
Tail Shape
Notched, Rounded, Square-tipped

Songs and Calls

Song a musical seedle-seedle-seedle, sweet, sweet, like that of Virginia's Warbler. Call a sharp plisk.
Call Pattern
Falling, Flat
Call Type
Chirp/Chip, Trill

Habitat

Oak-pine canyons. Breeds above 6000' in montane forests of pine, juniper, oak, and madrone; or in oak-maple-Arizona cypress habitats. Key plants in habitat used by nesting birds in Texas include Mexican pinyon, Grave's oak, gray oak, Texas madrone, beargrass, mountain mahogany, silktassel, mountain sage, Chisos prickly-pear, and pinyon-ricegrass. Prefers canyons and slopes. In winter in Mexico, found in humid pine-oak habitat with brushy understory.

Behavior

Eggs

Usually 4. Creamy with wreath of brown spots at larger end. Incubated by both parents, about 12 days.

Young

Both parents feed nestlings, but males do less than females, spending more time in defending territory. Young leave the nest 11 days after hatching, are independent of parents by a few days later.

Feeding Behavior

Moves rather deliberately while foraging, more like a vireo than like most active warblers. Typically, warblers in this genus do much probing of buds and flowers. In winter in Mexico, probably defends feeding territories, usually observed foraging alone or in pairs rather than in flocks.

Diet

Mostly insects. Diet not known in detail, undoubtedly feeds mostly on insects. Wasp galls from oaks, spiders, crane flies, and other flies are among favorite foods early in the breeding season. Nestlings are fed many small green moth larvae.

Nesting

Males defend nesting territories by singing and calling; sometimes physically attack territorial intruders. Nest: Placed on ground among rocks on bank of dry wash or at edge of talus slope. Nest (built by both sexes) is well shaded and hidden in dead leaves beneath grass tufts, rocks, or tree roots. Open cup-shaped nest of loosely woven, coarse grass and cedar bark strips, dead leaves, roots, and mosses; often lined with animal hair. Pinyon-ricegrass is a favorite nest material.

Climate Vulnerability

Conservation Status

Numbers in Texas vary from year to year, probably always fewer than 200 pairs. More numerous in northern Mexico, but would be vulnerable to loss of habitat.