Courtship behavior of captive American kestrels (Falco sparverius) exposedto polychlorinated biphenyls

Polychlorinated biphenyls (PCBs) adversely affect reproduction in birds. Ca ptive adult male and female American kestrels (Falco sparverius) were studi ed to investigate the potential behavioral and hormonal alterations during the courtship period resulting from clinical exposure to PCBs. American kes trels ingested 7 mg/kg/body weight/bird/day of a 1:1:1 mixture of Aroclors 1248, 1254, and 1260 through their diet of day-old cockerels. The dietary d osage of Aroclors resulted in environmentally relevant total PCB residues i n the eggs, averaging 34.1 mug/g wet weight (geometric mean). There was no difference between treatment and control birds in the circulating levels of total androgens (p = 0.44) or in 17 beta -estradiol (p = 0.29), one week f ollowing pairing. Male kestrels exposed to dietary PCBs exhibited significa ntly more sexual behaviors (p = 0.034) and flight behaviors (p = 0.026) tha n the control males. Sexual behaviors of male kestrels included; nest-box i nspections, solicitation of copulation, the offer of food to the female, an d giving the female food. The flight behaviors of the male included; flying from one perch to another and aerial display. In addition, the frequency o f male sexual behaviors were correlated (r = 0.605, p = 0.001) with total P CB residues in the eggs of their mates. A concurrent study found that these same PCB-exposed kestrels experienced a delay in clutch initiation as well as a greater number of completely infertile clutches.