both common and mew gulls breed colonially near water or in marshes, making a lined nest on the ground or in a small tree; colony size varies from 2 to 320 or even more pairs. usually three eggs are laid (sometimes just one or two); they hatch after 24–26 days, with the chicks fledging after a further 30–35 days. like most gulls, they are omnivores and will scavenge as well as hunt small prey. the global population is estimated to be about one million pairs; they are most numerous in europe, with over half (possibly as much as 80-90%) of the world population. by contrast, the alaskan population is only about 10,000 pairs.