Tuesday, July 31, 2012

San Francisco Bay Area Seabirds, Common Murre

San Francisco Bay Area Birds
SeaBirds of Marin, SF Bay and Gulf of the Farallones

Common Murre

Common Murre Scientific classification
  • Common Murre Kingdom: Animalia
  • Common Murre Phylum: Chordata
  • Common Murre Class: Aves
  • Common Murre Subclass: Neornithes
  • Common Murre Infraclass: Neognathae
  • Common Murre Superorder: Neoaves
  • Common Murre Order: Charadriiformes
  • Common Murre Suborder: Lari
  • Common Murre Family: Alcidae
  • Common Murre Subfamily: Alcinae
  • Common Murre Tribe: Alcini
  • Common Murre Genus: Uria
  • Common Murre Species: U. aalge
Common Murre Binomial name
  • Uria aalge
Finding Common Mures in the San Francisco Bay Area:
Common Murres are abundant in the San Francisco Bay Area. There are large colonies of Common Murres at the SouthEast Farallon Islands. Common Murres can be seen in captivity at the Monterey Bay Aquarium.
The Thin-billed or Common Murre (Uria aalge), also called Common Guillemot, is a relatively large auk. It spends most of its lifetime at sea, only coming to land to breed on rocky cliff shores or islands.
Adult birds are 38-46 cm in length with a 61-73 cm wingspan and weigh 945-1044 g when fully grown. They are black on the head, back and wings, and have white underparts. They have a thin dark pointed bill and a small rounded dark tail. The face becomes white in winter with a dark spur behind the eye. The chicks are downy in appearance with blackish on top and white below.
The bird is a fast, agile flier. The wings flap quickly and continuously in a straight line along the sea surface.
Other Information:
Courtship displays including bowing, billing and preening. The male points its head vertically and makes croaking and growling noises to attract the females. As usual for auks, the species is monogamous. The colonies are densely-packed, with up to twenty pairs occupying one meter square at peak season. The islands can also be inhabited by other species, which mingle with the murres to varying extent.
They usually nest in tight-packed colonies (known as "loomeries") and lay their eggs on bare rock ledges or ground. The eggs are pointed, so that if disturbed they roll in a circle rather than fall off the ledge. Eggs are laid between May and July for the Atlantic populations and March to July for those in the Pacific. The eggs vary in colour and pattern to help the parents recognize them, each egg is unique. Colours include white, green, blue or brown with spots or speckles in black or lilac. Both parents incubate the egg for 28 to 34 days, swapping in twelve hour shifts.
The chicks will leave the nest after 18 to 25 days, by simply jumping down into the sea, slowing their fall by fluttering as they are not yet able to fly. Once the young chicks have left the nest the male teaches them how to dive and catch fish for up to two months. The chicks learn to fly roughly two weeks after fledging. Up until then the male feeds and cares for the chick at sea. In migration the chick swims about 1000 km. Common Murres only breed when they reach four to six years old. The lifespan is about 20 years.

296876_ Manfrotto Lino Apparel Banner 336 x 280

No comments: