摘要: |
The Black-capped Vireo is a shrubland passerine that was federally listed as an endangered species in 1987. A substantial population nesting on Fort Hood, Texas, has been monitored since the year of its listing. This report presents results from that program, including extensive territory monitoring and bird banding. Results are presented in three forms; data collected on a regional basis, regional data combined for installation-wide totals, and data collected from study sites located within three primary regions. Regional and study site data collection protocols differed by the frequency and constancy of territory monitoring. These protocols provided installation-wide overviews as well as closer survey of local populations. In 1987 and 1988, nesting success throughout the installation was exceedingly low and brood parasitism was severe. An effective cowbird mitigation program has resulted in a notable reduction in the incidence of parasitism and nesting dynamics have dramatically improved. While vast improvement is clear, the viability of the installation-wide population is yet to be determined. Recent data suggested that vireos in some areas on the installation were producing young at levels indicative of self-maintaining populations, while others were not. The percentage of first time breeders increased, which suggests improved population stability. |