ANTICHOLINESTERASE EXPOSURE OF WHITE-WINGED DOVES BREEDING IN LOWER RIO-GRANDE-VALLEY, TEXAS

We studied exposure of breeding white-winged doves (Zenaida asiatica) to anticholinesterase compounds (organophosphorus and carbamate pestic ides) in the Lower Rio Grande Valley (LRGV), Texas. Widespread use of organophosphorus pesticides and dove population declines prompted the study. We collected breeding adult doves in May and July 1991 (n = 28) and July 1992 (n = 33) at 6 locations. We used depression of whole-br ain cholinesterase (ChE) activity (2 SD below control mean) to detect exposure; values from 4 hand-reared doves fed commercial pigeon chow s erved as the control. Mean brain ChE activity was lower (P < 0.027) th an the control sample at all 6 locations in 1991; 79% of the birds wer e diagnostic of exposure (> 16.1% ChE depression). Pooled 1992 field s amples also were lower (P < 0.036) than were control samples; doves fr om 4 of the 6 locations had brain ChE activity below (P < 0.088) contr ols. Overall, 39% of 1992 doves were diagnostic of exposure to anticho linesterase compounds. Higher exposure rates in 1991 were probably due to increased use of organophosphorus pesticides. Research is needed d ocumenting effects of sublethal exposure on white-winged dove producti vity.