The refuge has more than 215 bird species part or all year. Some of the birds at the refuge include the Painted Bunting, Black-crested Titmouse, Vermilion Flycatchers, Bushtits, Black-throated Sparrows, LeConte's Sparrows and Canyon Towhees. Redtails and Red-shouldered Hawks nest regularly as well as a few Cooper's Hawks. Almost half of the birds located at the refuge are neotropical migrants that breed in the U.S. and winter south of the border. The refuge offers some of the best bird watching and habitat left in Texas for two endangered songbirds- the Black-capped Vireo and the Golden-cheeked Warbler.

During the winter, the Black-capped Vireo is found on the West Coast of Mexico. The male vireos arrive in Texas from late March to mid-April. The male vireos set up territories that average 2 to 4 acres. Males often return to the same area in subsequent years. As soon as possible after she arrives, the female chooses a mate. Together, they build a single nest that is placed low in the vegetation and can be found in various species of oaks. The eggs are generally laid in May. Both adults participate in the incubation of the eggs and one of the pair is usually on the nest. Incubation lasts 13 to 17 days. The eggs hatch over a 2-day period. Newly fledged vireos remain near the nest. In August and sometimes as late as September, the Black-capped Vireos migrate back to Mexico for the winter. The Shin Oak Observation Deck is set in the middle of excellent Black-capped Vireo habitat. The deck is closed for a short period just as the vireos arrive to minimize the disturbance to the birds. Check the refuge web site for the specific dates the deck is closed each year. Once the birds settle into nesting activities, the observation deck is reopened to visitors. Typically, 3 to 5 territories of Black-capped Vireos are established within earshot and viewing distance from the deck. Please check our link section for other web sites with information on the Black-capped Vireos.

The Golden-cheeked Warblers winter in Mexico, Honduras, Nicaragua, and Guatemala. They arrive in Central Texas in mid-March and stay until about the end of July. The male warbler arrives first and establishes a territory of 3 to 6 acres. The female arrives a few days later and quickly selects a mate. The male warblers sing loud and defend their territories vigorously to attract their mate. The pair remains together throughout the nesting season. The female warbler builds the nest alone. The use of juniper trees that are at least 20 years old and 15 feet tall are essential to the nest building. The female pulls strips of bark from the tree for the main element of her nest. The presence of old growth Ashe juniper is vital to the species' survival. The female lays 3 or 4 eggs. For approximately the next 12 days, the female warbler incubates the eggs. The nestlings fledge at 9 days but remain near the adults for approximately 4 weeks. By the third week, the young birds are foraging for themselves and can fly as well as the adults. The Warbler Vista visitor area has the Cactus Rocks Trail that traverses prime Golden-cheeked Warbler habitat. Warbler Vista is open daily from sunrise to sunset. Please check our link section for other web sites with information on the Golden-cheeked Warbler.

The Refuge facilities are described in two current bird finding guides for Texas: Ro Wauer and Mark Elwonger's "Birding Texas" and Ed Kutac's "Birder's Guide to Texas". The Texas Ornithological Society and the Travis Audubon Society periodically schedule field trips to the refuge. The Master Naturalists also offer guided tours during festivals at the refuge.