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STRATEGY AND TECHNIQUES USED BY FORAGING SPOT-BILLED PELICAN PELECANUS PHILIPPENSIS IN PULICAT LAKE, ANDHRA PRADESH, INDIA

Vaithianathan Kannan

Foraging strategy and feeding techniques of the spot-billed pelican Pelecanus philippensis were studied from October 2010 to September 2012 in Pulicat Lake, Andhra Pradesh. The spot-billed pelicans were observed using visual techniques to catch prey. Of the 1061 observations in 2 years, 72.6% of prey were caught by striking with the wing opened, and 14.1% were caught by driving fish into shallows and 13.3% were caught with the wing closed. The rate of foraging attempts by pelicans fluctuates with season and coincides with prey abundance. During post-monsoon when the water level was high, spot-billed pelican search for prey more often, as the prey became widespread whereas in summer when the water level decreased, the concentration of the prey was lower, which helped the pelicans to catch prey in quick succession. Prey behaviour and habitat condition determine the selection of the visual foraging technique by the pelicans in Pulicat Lake. Pelicans were more successful in the early hours of the day (0600-1000 hrs) and the evening (1400-1800 hrs). Principal component analysis showed that prey handling time, month and water depth determined the foraging success of spot-billed pelicans.