Reproductive success and nest attentiveness of mallard ducks fed Aroclor 1254

A dietary dosage of 25 ppm Aroclor 1254 fed to nine-month-old mallards Anas platyrhynchos for at least a month before egg-laying had no detrimental effect on reproductive success or nest attentiveness when hens were allowed to incubate their own eggs. The treatment caused no effect on number of hens laying, date of first egg laid or clutch size. Fertility of eggs was greater among Aroclor-treated birds (87·7%) than among controls (73·2%). Aroclor may have stimulated males to come into reproductive condition sooner than controls. Hatching of fertile eggs and survival of ducklings to 3 weeks of age were similar in treated and control groups. The number of times off the nest per day and total time off the nest per day were the same for control and Aroclor-treated hens in days 14–17 of incubation.