Birds play an important role in the Preserve ecosystem by controlling insect populations as well as dispersing the seeds and pollen of native plants. The Balcones Canyonlands Preserve is home to a diverse number of birds, including two endangered species—the golden-cheeked warbler and the black-capped vireo. The black-capped vireo, like the golden-cheeked warbler, is a neotropical migrant, meaning that it migrates south to Central America during the winter. Nesting habitat for the vireo includes irregular, low scrubby growth that develops after a disturbance such as a fire or the clearing of trees.
With over 80 observed species, the Bull Creek Nature Preserve is an excellent place to learn about the complex and fascinating behavior of birds. For instance, the indigo bunting, a neotropical migrant recognized for its brilliant turquoise blue coloring, navigates using the same method as ancient sailors—by tracking the North Star. The northern mockingbird, the state bird of Texas, can be heard mimicking not only the calls of other birds, but also squeaking gates and backfiring cars. Turkey vultures, often seen roosting in tall trees or soaring overhead, are known for their extraordinary sense of smell. With the largest olfactory (smelling) system of all birds, they are able to smell carrion from over a mile away.
Although many birds on the Preserve can be found feeding and roosting in trees, birds occupy a wide variety of habitats. The greater roadrunner prefers cactus thickets to trees, running along the ground and catching snakes, lizards, and spiders. Other birds, like the hermit thrush and the chipping sparrow, can be seen foraging for insects or seeds on the ground in woodland areas. Areas along Bull Creek support wading birds like the great blue heron and green heron. The belted kingfisher, seen in trees along the creek as well as hovering over the water, is a crested bird with a large, thick bill that will plunge into the water headfirst to catch fish.
Apart from owls, most birds are diurnal, or active during the day. However, they can be difficult to see since many birds hide or seek shelter to avoid predation. Birds often will conceal themselves behind foliage and watch the observer through a small opening. When hiking in the Preserve, try moving slowly and being as quiet as possible to avoid scaring birds away. The best indicators of the various species in the area are songs and calls. For instance, the Carolina chickadee has a buzzy ‘chickadee-dee-dee-dee’ song. To see a bird that is singing or calling, try making a ‘spsh, spsh, spsh’ sound. Birds will often move closer to find out what is making the noise. For more birding tips, check out the Texas Parks and Wildlife Introduction to Birdwatching.