NOCTURNAL FORAGING BEHAVIOR OF BREEDING PIPING PLOVERS (CHARADRIUS-MELODUS) IN NEW-JERSEY

The nocturnal foraging behavior of breeding Piping Plovers (Charadirus melodus) was studied in New Jersey using a focal-animal approach in 1989 and 1990. More than 30% of the variation in the number of plovers foraging at night was explained by stage of the breeding cycle, tidal stage, and year. The greatest numbers of adult plovers fed in the intertidal zone during the prenesting and fledgling stages of the breeding cycle. Piping Plovers were more likely to be observed feeding during late ebb and early flood tides, than other times. Time devoted to feeding per 2-min sample was similar at each study site but differed significantly during the tidal stages. Pecking rate was higher during late ebb and early flood tides than late flood and early ebb tides. Time devoted to being alert varied depending on stage of the breeding cycle. Prenesting plovers and individuals with fledglings fed longer and were alert less per 2-min sample than plovers engaged in incubation or brood rearing. The nocturnal peck rate of Piping Plovers was considerably lower than daytime levels. Plovers foraging at night had significantly lower peck rates when disturbed. Abundance of intertidal polychaetes varied according to tidal stage and, where present, they constituted the main food of the plovers. We suggest that nocturnal foraging is a natural behavior pattern in Piping Plovers although it may vary in intensity. Future management should include the assessment of nighttime recreational use of beaches where Piping Plovers breed.