The diet of Markham's Storm Petrel Oceanodroma Markhami on the central coast of Peru

Abstract

We studied the diet of Markham's Storm Petrel Oceanodroma markhami on Paracas Peninsula and La Vieja Island, central Peru, in 1996, 1999 and 2000. A total of 95 samples was collected from adults captured in mist nets at breeding colonies, using the water-offloading technique. The diet was composed of fish (54% by mass), cephalopods (36%) and crustaceans (10%). Among the fish, Peruvian Anchovy Engraulis ringens was the main prey (27.2% of the total mass), followed by fish of unknown identity (16.7%). The Pelagic Squat Lobster Pleuroncodes monodon was the main crustacean prey (9.4%); the oceanic octopus Japetella sp. was the most frequent cephalopod eaten. Prey composition varied among years, before and after El Nño 1997/98. Fish was the main prey in samples during 1999, when anchovy was first observed in the diet (43% by mass). Cephalopods were the main prey in 1996 (44%) and 2000 (84%). Fish prey suggests both inshore and offshore feeding, while cephalopods suggest offshore feeding only. The observed pattern of the diet of the Markham's Storm Petrel indicates opportunities feeding.