The herring gull is a supreme opportunist and scavenger that feeds on discarded fish offal, refuse, bird chicks, mammals, eggs, worms and other invertebrates (7). It breeds in colonies (7) and the nest is usually an untidy heap of grass, seaweed and other vegetation (8). Two to six eggs, which are variable in colour and patterning, are laid after April. Incubation, which is carried out largely by the female (7), takes between 25 and 27 days (8). Both parents share parental care of the downy chicks, which fledge after around 30 days (7).