Thick-billed Murre

The Thick-billed Murre, or Brünnich's Guillemot, is a robust member of the auk family, Alcidae. It is the largest extant species within its family since the extinction of the great auk. The bird is characterized by its black upperparts and white underparts, with a distinctive long and pointed bill. The Pacific subspecies, known as Pallas' Murre, is notably larger, particularly in bill size.

Identification Tips

When identifying the Thick-billed Murre, look for the black head, neck, back, and wings contrasted with white underparts. The bill is long, pointed, and during the breeding season, it features a white gape stripe. The tail is small and rounded. In winter, the face becomes whiter. Their calls are a series of harsh cackles at breeding colonies. In flight, they appear shorter than the similar Common Murre due to their thicker bill and darker plumage.

Habitat

These birds are pelagic, spending their lives in sub-polar and polar seas, preferring waters below 8°C. They come ashore only to breed, forming dense colonies on cliff faces.

Distribution

The Thick-billed Murre is found across the Northern Hemisphere's polar and sub-polar regions, with four subspecies distributed between the Atlantic and Pacific Oceans of North America and the Russian Arctic.

Behaviour

Murres exhibit strong and direct flight with rapid wingbeats, necessitated by their short wings. They are adept divers, capable of reaching depths up to 150 meters and can dive for several minutes. Their foraging often involves long trips from their nesting sites.

Song & Calls

At breeding colonies, the Thick-billed Murre is vocal with a variety of harsh cackling calls. However, it remains silent when at sea.

Breeding

Breeding occurs on narrow cliff ledges, where they lay a single egg directly on the rock. Both parents incubate and care for the chick. The young leave the nest by jumping into the sea, guided by a parent, and remain with the male for approximately eight weeks at sea.

Similar Species

The Common Murre is similar in size but can be distinguished by its thinner bill without the white gape stripe and its lighter head and back. The bridled morph, with a white eye-stripe or bill-stripe, is not found in the Thick-billed Murre.

Diet and Feeding

Their diet primarily consists of fish like Gadus spp. and Arctic cod, as well as the pelagic amphipod Parathemisto libellula. They also consume other crustaceans, polychaetes, and molluscs.

Conservation Status

The Thick-billed Murre is classified as Least Concern, with an estimated global population of 15 to 20 million individuals. However, they face threats from egg harvesting, hunting, pollution, and climate change, which may impact their sea-ice associated habitat.

As a Vagrant

The Thick-billed Murre is a rare vagrant in European countries south of its breeding range. It has been recorded as far south as Florida in the western Atlantic and California in the Pacific.