Diet and Foraging

Microhabitat for Foraging

Gray Gull forages actively at sea and on the beach; at sea, it feeds on zooplankton swarms and shoals of fish (32 Duffy, D. C. (1983). The foraging ecology of Peruvian seabirds. Auk 100(4):800–810. Close ). Occasionally, it forages on fish escaping from other animals, like South American Sea Lions (Otaria flavescens; 32 Duffy, D. C. (1983). The foraging ecology of Peruvian seabirds. Auk 100(4):800–810. Close ).

Food Capture and Consumption

Feeds much like sandpipers in the wave-washed littoral zone, taking mole crabs from 1 hour before low tide to 2 hours after. It surface-plunges for fish and nereid worms, scavenges in harbors, and follows fishing boats (33 Weichler, T., S. Garthe, G. Luna-Jorquera, J. and Moraga (2004) Seabird distribution on the Humboldt Current in northern Chile in relation to hydrography, productivity, and fisheries. ICES Journal of Marine Science 61: 148–154. Close ).

Gray Gull has a duplex retina, with a high number of rods, allowing them to see at night (34 Emond M. P., R. McNeil, T. Cabana, C. G. Guerra, and P. Lachapelle (2006). Comparing the retinal structures and functions in two species of gulls (Larus delawarensis and Larus modestus) with significant nocturnal behaviours. Vision Research 46: 2914-2925 Close ). It also adapts to the dark faster than other nocturnal gulls, such as the Ring-billed Gull (Larus delawarensis) (34 Emond M. P., R. McNeil, T. Cabana, C. G. Guerra, and P. Lachapelle (2006). Comparing the retinal structures and functions in two species of gulls (Larus delawarensis and Larus modestus) with significant nocturnal behaviours. Vision Research 46: 2914-2925 Close ). This might allow them to feed at night, and move to their colonies in the middle of the Atacama Desert.

Major Food Items

Feeds mainly and sometimes exclusively on mole crabs (Emerita analoga). It also feeds on fish (especially on Peruvian Anchovy [Engraulis ringens] and Sardines [Clupeidae]), nereid worms, and offal. Chicks are primarily fed fish, with adults making only one feeding trip per day to the desert areas in which it breeds. In an extralimital record in Mexico, it was recorded feeding on ray carcasses tossed away by people (Montejo and McAndrews, eBird).

Nothing known.

Nothing known.

Nothing known.

Nothing known.