FORAGING FLIGHTS, REPRODUCTIVE SUCCESS AND ORGANOCHLORINE CONTAMINANTS IN CATTLE EGRETS NESTING IN A RESIDENTIAL AREA OF BRYAN, TEXAS

This study was designed to determine reproductive success, habitat use and foraging trips of Cattle Egrets (Bubulcus ibis) nesting in the sm all city of Bryan, Texas and to compare residues of persistent organoc hlorine compounds in eggs of Cattle Egrets from recent years with data collected in the past. Mean clutch size and reproductive success of e grets nesting in Bryan in 1993 and 1994 were not different from the st ate average reported for egrets in non-urban habitats. Cattle egrets f lew non-randomly in and out of the colony predominantly alone or in pa irs and foraged mostly in pastures with cattle at 10-15 km around the colony. The only organochlorine residues found at detectable levels we re DDE and PCBs. Mean DDE levels in eggs were mostly at near backgroun d levels and were significantly lower than those reported for Cattle E grets in the 1970s.