INFANTICIDE OF WEDGE-TAILED SHEARWATER PUFFINUS PACIFICUS CHICK AT MARINE CORPS bASE HAWAII

Colonial seabirds are highly susceptible to the effects of conspecific aggression . Their close proximity during the nesting period may result in an increased frequency of aggressive encounters and facilitate their detection (Mock 1984, Clode 1993, Parkes 2005) . In seabirds, conspecific aggression can occur between adults, between adults and chicks or between chicks, and is thought to increase when environmental conditions are poor (Ashbrook et al . 2008) . In years of low food availability in Common Guillemots (Uria aalge), adults leave chicks unattended for longer periods, resulting in increased attacks from neighboring adults (Ashbrook et al . 2008) . Similarly, Fetterolf (1983) found that low food availability not only increased attacks on Ring-billed Gull Larus delawarensis chicks from neighboring adults, but also increased the frequency of chicks leaving the nest to beg for food from neighboring nests . This behavior can result in either voluntary feeding or aggression, depending on the reaction of the neighboring adult (Ramos 2003) . There is an evolutionary “arms race” between poorly fed chicks attempting to survive and parents attempting to increase their own fitness without wasting efforts on non-filial chicks (Pierotti 1991, Brown 2000) . Inherent in this scenario is the competitive struggle between nonsibling chicks when an intruder attempts kleptoparasitism .