Daily Activity Budgets and Population Size of American White Pelicans Wintering in South Louisiana and the Delta Region of Mississippi

摘要

Twenty-one American White Pelicans (Pelecanus erythrorhynchos) were captured and fitted with radio-transmitters in South Louisiana and the delta region o f Mississippi during the winter and early spring of 1994-1997. The pelicans were monitored to determine their daily activity budgets while using different habitats such as catfish ponds, crawfish ponds, rivers, lakes, and bayous. Pelicans foraging at catfish ponds spent about 4% of their day foraging and 96% loafing, while pelicans foraging in other habitats spent about 28% of their day foraging and 72% loafing. For an individual bird, the mean number of foraging sessions per day was 2.5(± 0.53 SE) and the mean length of each foraging session was 66.7 min. (+8.08 SE). Aerial censuses were also conducted to determine the numbers o f pelicans in the delta region o f Mississippi. Each year the numbers o f pelicans wintering in the delta region o f Mississippi peaked in February and March, corresponding with spring migration. Pelican numbers reached approximately 4,600 during February and March 1996. Pelicans were observed foraging in larger flocks for shorter periods o f time on catfish ponds than in other habitats.