Thick-billed Murre
Thick-billed Murre
Uria lomvia
At a Glance
A large, robust auk, swimming and diving deep in cold ocean waters. Very similar to Common Murre. The two are found together in many areas, even nesting on the same ledges of rocky northern islands, but the Thick-billed has its center of abundance farther north. Despite major recent declines, its population in the eastern Canadian Arctic undoubtedly runs into the millions.
All bird guide text and rangemaps adapted from by Kenn Kaufman漏 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Auks, Murres, Puffins, Upright-perching Water Birds
IUCN Status
Least Concern
Habitat
Coasts and Shorelines, Open Ocean
Region
Alaska and The North, California, Eastern Canada, Mid Atlantic, New England, Northwest, Western Canada
Behavior
Direct Flight, Erratic, Rapid Wingbeats, Swimming
Population
15.000.000
Range & Identification
Migration & Range Maps
Some remain through winter as far north as open water allows, including around openings in pack ice. Others move south. Regular in winter on waters off New England, has strayed farther south. In west, very rare south of Alaska in winter.
Description
18" (46 cm). Much like Common Murre. Seen close, slightly thicker bill shows white mark at gape. Blacker back (hard to see without direct comparison). In summer, Thick-billed may show white coming up higher in point on chest; in winter, it may have more black on face than Common Murre.
Size
About the size of a Crow, About the size of a Mallard or Herring Gull
Color
Black, White
Wing Shape
Broad, Pointed
Tail Shape
Short
Songs and Calls
Similar to Common Murre: low, purring murrrr; also croaks and growls on breeding grounds.
Call Pattern
Flat, Undulating
Call Type
Odd, Rattle, Raucous, Scream
Habitat
Ocean, nesting colonially on ledges of sea cliffs. Favors very cold ocean waters of Arctic; when not nesting, often very far from land over deep waters. May associate with edges or openings in pack ice. Nests on rocky coasts or islands with steep cliffs.
Sign up for 探花精选's newsletter to learn more about birds like the Thick-billed Murre
Behavior
Eggs
One. Very variable, usually whitish, tan, blue, or green, with markings of brown and black. Incubation is by both sexes, 30-35 days. One parent is almost always at nest throughout nesting cycle.
Young
Fed by both parents. Adults often forage many miles away from colony. Young leaves nest at 15-30 days, before able to fly; glides down to sea, accompanied by adult male. Young evidently is accompanied and cared for by male for several weeks after leaving nest.
Feeding Behavior
Forages while swimming underwater. May dive to more than 200' below surface.
Diet
Mostly fish. Diet is primarily fish in summer (and young are fed almost entirely on fish); may include more crustaceans in winter. Fish in diet include cod, herring, capelin, sand lance, sculpin, many others. Crustaceans eaten include shrimp, amphipods, mysids, copepods. Also eats some marine worms, squid.
Nesting
Probably older than 3 years at first breeding. Nests in colonies, some very large. Some pair formation may occur before arrival at colony. At nest site, members of pair bow, nibble at each other's bills; may pick up pebbles and present them to each other. Nest site is on cliff ledge; may use narrower and smaller ledges than Common Murre. No nest, egg laid on bare rock.
Conservation
Conservation Status
Population still in the millions, but reported declines of 20%-50% in some large colonies in recent decades are cause for concern. Eggs and adults harvested for food by natives in some Arctic areas. Bigger threats to survival are large numbers killed in fishing nets, and vulnerability to pollution, oil spills, and effects of climate change.
Climate Threats Facing the Thick-billed Murre
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.