The Texas population is found in the rugged canyon country in the western region of the state, mainly along the Rio Grande, which forms a boundary with the states of Coahuila and Chihuahua, Mexico. The population is geographically isolated and has not been manipulated through cross-fostering or hacking captive raised peregrines. Over a 22 year period, from 2 to 15 breeding areas have been closely monitored. In only 7 of 22 years has production reached, or exceeded the 1.25 young fledged per site considered necessary for population stabilization. Nest failure in the incubation stage is a common occurrence.
Contaminants are a possible factor responsible for poor reproductive success.
In addition, recruitment rate is very low, sometimes taking several years for a lone adult to attract a mate. Opportunistic collections of peregrine feathers and egg shell fragments, as well as selected prey species have been analyzed for possible DDE, mercury, and other contaminant effects. These results will be combined with future sample analyses to understand possible factors of low reproduction. Current and future research needs will continue to focus on contaminants, reproductive success and more extensive surveys in the nearby mountains of Coahuila, Mexico. Funding for this research is provided by the Nongame and Urban Program, private donations from organizations and individuals, and from the sale of peregrine T-shirts.