Courtesy Kenn Kaufman
The breeding range for the Golden-cheeked Warbler is limited to central Texas: the Edward's Plateau, the Lampasas Cut Plain, and the Central Mineral Region, also known as the Llano Uplift. Its range has shrunk drastically, from more than 40 counties to 25 or fewer. Estimated at approximately 66,000 acres in 2003, the largest section of continuous habitat exists on Fort Hood, Texas. In winter, this warbler is confined to a narrow band in Central American foothills and mountains, mostly between 3,300 and 8,300 feet, from southern Mexico to Guatemala and Honduras. All year round, its distribution is patchy.
Only in Texas, breeding territories are established in Ashe juniper forests with various oaks: Lacey, Live, Shin, and Spanish. This habitat occurs on limestone hills and canyons. The forest must be mature, with junipers reaching at least 17 feet and oaks measuring about 20 feet; and forest patches need to be large, at least 250 acres. The border of the forest is used, but this warbler successfully raises more young when nests are well within the forest. Migration and wintering habitats are similar: a mixed deciduous and evergreen forest, dominated by pines, between 3,300 and 8,300 feet.
The Golden-cheeked Warbler appears to be completely insectivorous. Hopping over small branches and twigs, it plucks insects from all surfaces. It can reach its prey by flying out to snatch it from the air or hovering in front of a leaf or twig to grab it. Only the summer diet has been recorded, and it includes aphids, beetles, flies, leafhoppers, moths and their larvae, and spiders. Caterpillars are especially important for feeding to young warblers.
In early to mid-March, the male Golden-cheeked Warbler establishes a territory, about 10 acres in area. Older males usually reclaim the previous year's site and immediately defend it with song, chases, and physical attacks against rival males. Monogamous pairs form for the season. Females probably choose a spot for the nest, usually in an Ashe juniper tree, 16-23 feet above the ground. While the male defends the territory, the female stacks strips of juniper bark in a forked branch, on which she then weaves a cup of bark strips, lined with thin pieces of grass, animal hair, or down. The nest is stuck together with spider silks and insect cocoons.
For 10-12 days, she incubates 3-4 whitish eggs marked with delicate brown or purplish dots. Practically naked, blind, and barely able to raise their heads, the hatchlings grow quickly and leave the nest in 9-12 days. Usually, the adults separate the brood and manage one part on their own, but the entire family may stay on the territory together, until the young are independent about 1 month after leaving the nest.
Many Golden-cheeked Warblers only stay in Texas for about three months, from March to June, and all of them leave by the fall. Usually in flocks with other songbirds, spring migrants travel along Mexico's Sierra Madre Oriental and arrive on the breeding grounds as early as the first week in March. Following the same path, most post-breeders and juveniles depart by mid-June, and only a few linger into August.