New paper on foraging behaviour in gulls
Through GPS tracking, the resarchers were able to follow 19 individuals of lesser black-backed gulls (Larus fuscus) across 3 years, resulting in 1038 traced foraging trips. Among other things they found that 21.2 % of foraging trips were predominantly terrestrial, 9.0 % were a mix of terrestrial and marine, and 68.5 % were exclusively marine. The terrestrial trips were more frequent when departing around sunrise, whereas marine trips occurred throughout the day. Additionally, trips with mostly land-based foraging decreased as the breeding season progressed, suggesting dietary switching coincident with the onset of chick provisioning. To the paper in Movement Ecology.
The proportion of foraging trips by GPS tracked gulls classified as land, sea, or mixed for the breeding period (a) and per hour based on time of departure (b). a For each 5 day period from all 3 years pooled (also see Additional file 8 where years are separated). The breeding stages are indicated (vertical broken grey lines). Note that the pre-laying period was calculated from 2012 & 2013 only as data for 2011 were unavailable. b Proportion of all foraging trip departures occurring each hour relative to time of sunrise performed by the gulls with data pooled for all breeding stages and years. Trip types are indicated (following same colors as panel a). Period of day is indicated, with night (dark grey), and day (light yellow); as the length of night was not constant throughout the study the maximum- (light grey) and minimum- (dark grey) night duration are indicated.