Black-capped Vireo breeding habitat in north-central Texas
Authors: A. M. Long, H. A. Mathewson, D. H. Robinson, J. A. Grzybowski, M. L. Morrison
The Black-capped Vireo (Vireo atricapilla), listed as endangered by the U.S. Fish and Wildlife Service, breeds in southwestern Oklahoma, central Texas, and northern Mexico (Grzybowski 1995, Wilkins et al. 2006). Its breeding habitat is typically composed of low, deciduous shrubs and trees of irregular heights, heterogeneity that may result from local environmental conditions (e.g., soil type, climate) or must be maintained by periodic disturbance (e.g., wildfire, prescribed burning) (Graber 1961, Grzybowski 1995). Habitat loss (e.g., land-use conversion, vegetation succession), habitat degradation (e.g., grazing by domestic livestock, browsing by wild herbivores), and nest parasitism by the Brown-headed Cowbird (Molothrus ater) precipitated the species’ decline (Ratzlaff 1987). Since the vireo’s listing as endangered (Ratzlaff 1987), most of its management (e.g., cowbird removal, habitat manipulation) and research has taken place at a few prioritized study sites in Texas (e.g., Grzybowski et al. 1994, Stake and Cimprich 2003, Pope et al. 2013) and Oklahoma (e.g., Grzybowski et al. 1994). Smith et al. (2012) added to our understanding of vireo-habitat relationships in the southwestern portion of the breeding range in Texas. Information regarding the vireo’s occurrence, abundance, and reproductive status in relation to habitat characteristics is still lacking for north-central Texas.