Marbled Murrelets as initiators of feeding flocks in Prince William Sound,Alaska

I sought to determine which seabird species initiated small, ephemeral, mul tispecies feeding flocks in Prince William Sound, AK (PWS). I observed 47 f eeding flocks at fire sites during June 1996 and determined the initiating species at 34. All of the latter flocks were initiated by pursuit divers, o f which 76.5% were Marbled Murrelets (Brachyramphus marmoratus), the most a bundant seabird in PWS. Formation of feeding flocks followed either of two scenarios: 1) larids were attracted to a feeding location by the presence o r activity of Marbled Murrelets (26.9%), or 2) both larids and murrelets we re present anti flock feeding began after the murrelets dove from the surfa ce (50.0%). Other principal participants were Black-legged Kittiwakes (Riss a tridactyla) and Glaucous-winged Gulls (Larus glaucescens).