Organochlorine pesticides in plasma of migrating peregrine falcons at Padre Island, Texas, Spring 1978-80 vs. Spring 1984

A spring concentration of migrating Peregrine Falcons (Falco peregrinus) was first discovered at Padre Island, Texas, in April 1978. The birds were first captured and blood-sampled for monitoring residue burdens and trends in the late 1970' s. Only 29 Peregrines were sampled in 1978 and 1979, but 111 were sampled in 1980. The initial investigation showed that DDE in the plasma of spring migrants returning from Latin America for the first time declined significantly during the study (through 1980). In the spring of 1984, 48 Peregrines were captured at Padre Island with blood samples again collected. This report will compare plasma residue data from the earlier study with residues obtained in 1984.