This is an egg of the Glaucous Gull (Larus hyperboreus), a very large Arctic gull belonging to the family Laridae (gulls).

Glaucous Gull eggs are typically oval to sub-pyriform (pear-shaped), measuring approximately 7.2–8.0 cm in length and 4.9–5.5 cm in breadth. The ground colour varies from pale buff to olive or brown, marked with darker brown, grey or purplish blotches and spots, which provide effective camouflage against tundra and rocky substrates.

Location:
Glaucous Gulls breed in high Arctic regions across the northern hemisphere, including parts of Canada, Greenland, Iceland, Norway and Russia. They nest on coastal cliffs, rocky islands and low tundra near the sea. Outside the breeding season, they disperse southwards and are regular winter visitors to the United Kingdom and other northern European coasts.

Average Size:
Length: ~7.2–8.0 cm.

Breadth: ~4.9–5.5 cm.

Family:
Laridae (gulls)

Species:
Larus hyperboreus

Ecological Role:
Glaucous Gulls are opportunistic predators and scavengers, feeding on fish, seabirds, eggs, carrion and marine invertebrates. As both predator and scavenger, they play an important role in Arctic coastal ecosystems.

Movement and Behaviour:
This species is migratory, breeding in Arctic regions and moving south in winter. It is a powerful flier and engages in both scavenging and active predation, including kleptoparasitism (stealing food from other birds).

Reproduction & Eggs:
Nests are shallow scrapes lined with vegetation, moss or feathers, placed on the ground, cliffs or rocky ledges. A typical clutch consists of 2–3 eggs. Both parents share incubation, which lasts approximately 27–30 days. Chicks hatch down-covered and mobile (precocial), remaining near the nest but dependent on parental feeding and protection. They typically fledge after about 6–8 weeks.

Conservation Status:
Globally assessed as Least Concern by the International Union for Conservation of Nature (IUCN), although some populations may be affected by environmental contaminants, climate change and shifts in Arctic food webs.

Collection Date:
Collected in Iceland on the 14th of June 1900.