Seasonal Changes in Day and Night Foraging of Willets in Northeastern Venezuela

• Published in: The Condor (Los Angeles, Calif.) Calif.), 1994-08, Vol.96 (3), p.734-738
• Main Authors: Rompré, Ghislain, McNeil, Raymond
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal behavior; Animal populations; Animal, plant and microbial ecology; Animals; Aves; Biological and medical sciences; Birds; Catoptrophorus semipalmatus; Demecology; Foraging; Freshwater; Fundamental and applied biological sciences. Psychology; Lagoons; Ornithology; Seasonal migration; Seasonal variations; Seasons; Tropical environments; Tropical regions; Vertebrata; Waterfowl; Winter
• ISSN: 0010-5422; 1938-5129; 2732-4621
• DOI: 10.2307/1369476

We studied whether or not the proportion of foraging Willets (Catoptrophorus semipalmatus), a Nearctic migrant in northeastern Venezuela, varies seasonally on the wintering grounds in tropical environment as a function of energetic requirements. Data on the number of birds feeding and roosting were collected once or twice a week, from 19 October 1991 to 5 May 1992, during diurnal and nocturnal observation periods, each lasting 12 consecutive hours. There was a correlation between the seasonal changes in the proportion of Willets foraging (day + night) and the seasonal variations in the fat content of other individuals collected in the same region. Willets fed as often during nighttime as during daytime, except in autumn when they fed more during darkness. Compared to December and January, the percentage of birds feeding was greater in October and November. In addition, proportionally more birds fed, both during daytime and nighttime, in preparation for spring migration than in October-November.