First report on habitat use and trip parameters of Yellow-footed Gulls Larus livens during the breeding and post-breeding period

Abstract Biologging has allowed collecting unprecedented detailed information about the biology and behavior of many species. GPS tracking technology has significantly advanced our understanding of gull ecology; however, research remains limited for endemic and tropical gull species. Here, we tracked Yellow-footed Gulls ( Larus livens ) at Gaviota Island in La Paz, Mexico, to obtain information on their habitat use and trip parameters between the early breeding (incubation and rearing small chicks), late breeding (large chicks and fledglings), and post-breeding period. During the early breeding period, Yellow-footed Gulls ( n = 6) showed greater proportional use of at-sea habitats, spent less time away from their central location (h), and covered greater total trip distances (km). In contrast, the same individuals tracked during late breeding period ( n = 5) showed greater proportional use of intertidal zones, spent more time away from their central location (h), and covered shorter total trip distances (km). During the post-breeding period ( n = 4), gulls showed greater proportional use of human-altered habitats such as fishing ports, or aquaculture areas; and although gulls seldom traveled > 30 km, one individual moved > 200 km away from the colony. Differences in habitat use and trip parameters across periods were attributed to breeding requirements and prey availability. Although our sample size was small, this study furthers our understanding of the behavior of this poorly known endemic gull species from the Gulf of California.