Breeding among Mew Gulls occurs in colonies on the coasts of Scandinavia, Finland, Russia, Great Britain, Ireland, Denmark, Poland, Germany, Alaska, northwest Canada and on occasion, Holland and France. They are usually already paired when they arrive in March and early April at the breeding grounds. During the initial courtship the female will make primary contact, begging the male for food in a crouched posture. They will generally create large nests, which are almost entirely constructed by the female, while the male keeps his distance, occasionally bringing building materials. The nest itself will be made up of many different materials, such as seaweed, twigs, mosses, bark, grasses, and weed stalks.Mew Gulls tend to build their nests on bare rocks or hummocks.(Bent, 1963; Harrison, 1983; Royal BC Museum, 1995; USGS, 2001; Ehrlich, Dobkin & Wheye, 1988)
Mating System: monogamous
Mew Gull eggs are a light brown/olive with brown markings, and are about 57 mm(2.2in) in length. They are laid in March and early April during the breeding season. The female gull will lay her first egg at anytime during a 24 hour period, but the majority of 2nd and 3rd eggs are laid from midday to evening. The eggs are incubated by both sexes at intervals of two to three hours, and will begin to hatch at around three to four weeks. When the chicks are hatched, they are tended by both parents. For the first four days, they will feed the hatchlings insects and small fish. At 20 days the young will begin to forage for food on their own, feeding on insects and their larvae, although they will still occasionally be fed by the parents, and will not be fully independent until about eight weeks.
The young gulls will stay in the nest until near to full growth, all the while being camoflouged by thick, speckled down. However, because many young gulls will often cannibalise their younger or weaker siblings, it is a rarity for more than one chick to survive.(Time Life, 1976; Skutch, 1976; Felix, 1998; Bent, 1963; Ehrlich, Dobkin & Wheye 1988)
Breeding season: March and early April
Range eggs per season: 3 to 5.
Average eggs per season: 3.
Average time to hatching: 25 days.
Average fledging age: 35 days.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)
Average time to hatching: 23 days.
Average eggs per season: 3.
Parental Investment: precocial ; male parental care ; female parental care