Resources at Risk
A number of federally threatened or endangered species are known to occur in Hays County, including the golden-cheeked warbler, black-capped vireo, and various aquatic species. Several poorly known cave-adapted invertebrate species are also expected to occur within Hays County.
Hays County also includes a number of sensitive aquatic and geologic features, including important springs and aquifer recharge features.
The Hays County Habitat Conservation Plan will identify important natural resources in the County, evaluate potential threats to their health, and provide a program for protecting them for future generations. The focus of the plan will be to protect habitat for endangered species. However, conserving habitat for these target species can also benefit other species that rely on similar habitats, as well as unique landscape features like springs and caves.
Golden-cheeked Warbler (Dendroica chrysoparia)
Description: The golden-cheeked warbler is a small, insectivorous bird. Adult males have black on the crown, nape, back, throat, and upper breast. The wings are black with two white wing bars. The cheeks are a bright golden-yellow with a black eyeline. The underparts are white streaked with black on the flanks. Adult females are similar, but duller; the crown and back are olive-green with some black streaking (Oberholser 1974, Farrand 1983). Golden-cheeked warbler photo by Earl Nottingham, TPWD (2005).
Habitat: In Texas, the golden-cheeked warbler uses mature juniper-oak woodlands as nesting habitat (Wahl et al. 1990, FWS 1992). Ashe juniper (also called "cedar") and various oak species are the dominant tree species throughout the warbler's breeding range. Bark shreds of mature Ashe juniper are used by the species for constructing nests. Golden-cheeks are typically found in areas of steep slopes, canyon heads, draws and adjacent ridgetops (Pulich 1976, Ladd 1985).
Status: The U.S. Fish & Wildlife Service listed the golden-cheeked warbler as federally endangered in 1990. The population decline of the golden-cheeked warbler is a result of various factors related to habitat destruction and fragmentation (Wahl et al. 1990, USFWS 1992, Ladd and Gass 1999). Three primary causes for the decline in the amount of suitable warbler habitat are land clearing for agricultural use, land development, and reservoir construction (Oberholser 1974). Nest parasitism by brown-headed cowbirds may also have contributed to the golden-cheeked warbler's population decline (Pulich 1976, USFWS 1992).
Black-capped Vireo (Vireo atricapilla)
Description: The black-capped vireo is a small, insectivorous bird. Characteristic features of the male include a black crown, nape and face, and white "spectacles" formed by white eye-rings connected by a white band. Females are similar, but duller, and have a slaty-gray cap. The back of the bird is olive green, the wings and tail are blackish with yellow-green edgings, the breast and belly are white with greenish yellow flanks, and the wings have two pale yellow wing bars (Oberholser 1974, Farrand 1983). Black-capped vireo photo by TPWD.
Habitat: : The black-capped vireo uses patchy clusters of shrubs and thickets, with a few scattered trees (Graber 1957 and 1961, USFWS 1991, Grzybowski 1995). Ashe juniper is usually not the dominant species, although it may be co-dominant with oaks. The shrub layer in vireo habitat is usually four to ten feet high, with leaf cover extending densely to the ground. Vegetation structure at this level is necessary because vireos place their nests at an average height of only about three feet from the ground (Graber 1961, USFWS 1991, Grzybowski 1995). Black-capped vireo habitat photo by USFWS.
Status: The U.S. Fish & Wildlife Service listed the black-capped vireo as federally endangered in 1987. The recovery plan for the vireo identifies several threats/reasons for listing, including: population decline, low reproductive success, low recruitment of breeding age birds in colonies, nest parasitism by cowbirds, direct habitat destruction, habitat loss or deterioration through control of natural processes, and indirect effects of land use (USFWS 1991).
Hays County includes several major, mapped springs (including San Marcos Springs and Jacob's Well). Many of the threatened or endangered species in Hays County are salamanders, insects, fish, or plants that occur in association with spring outlets.
Perennial waterways provide high quality aquatic habitat for wildlife and recreational opportunities for people, including Blanco River, San Marcos River, Pedernales River, Cypress Creek, and Onion Creek. The County includes approximately 70 miles of river and 430 miles of named streams. San Marcos River photo by Earl Nottingham, TPWD (2005).
Both the Edwards Aquifer and Trinity Aquifer outcrop within Hays County, and provide drinking water to much of the population.
Farrand, J., Jr. (ed.). 1983. The Audubon Society master guide to birding. 3 Vols. Alfred A. Knopf, New York. 1244 pp.
Graber, J.W. 1957. A bioecological study of the black-capped vireo (Vireo atricapillus). Ph.D. dissertation. University of Oklahoma, Norman, OK. 203 pp.
Graber, J.W. 1961. Distribution, habitat requirements, and life history of the black-capped vireo (Vireo atricapilla). Ecol. Mono. 31:313-336.
Grzybowski, J.A. 1995. Black-capped vireo (Vireo atricapillus). In The Birds of North America, No. 181 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences of Philadelphia, and The American Ornithologists' Union. Washington, D.C.
Ladd, C.G. 1985. Nesting habitat requirements of the golden-cheeked warbler. M.S. thesis. Southwest Texas St. Univ., San Marcos, Texas. 65 pp.
Ladd, C., and L. Gass. 1999. Golden-cheeked warbler (Dendroica chrysoparia). In The Birds of North America, No. 420 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA. 24 pp.
Oberholser, H.C. 1974. The bird life of Texas. 2 vols. University of Texas Press, Austin. 1069 pp.
Pulich, W.M. 1976. The golden-cheeked warbler: a bioecological study. Texas Parks and Wildlife Dept., Austin, Texas. 172 pp.
U.S. Fish and Wildlife Service (USFWS). 1991. Black-capped vireo (Vireo atricapillus) recovery plan. FWS, Austin, TX. 74 pp.
U.S. Fish and Wildlife Service (USFWS). 1992. Golden-cheeked warbler (Dendroica chrysoparia) recovery plan. Albuquerque, New Mexico. 88 pp.
Wahl, R., D.D. Diamond and D. Shaw. 1990. The golden-cheeked warbler: a status review. Prepared for the U.S. Fish and Wildlife Service, Fort Worth, Texas. 63 pp. plus appendices and maps.