Thursday, August 25, 2011

Black Legged Kittiwake

Black Legged Kittiwake photo © Jorma Tenovuo Black Legged Kittiwake (Rissa tridactyla)

Adults are roughly 16 inches (40 cm) in length with a wingspan of 35-40 inches (90-100 cm). They have a white head and body. Their backs are grey, and their grey wings are tipped solid black. They have black legs and a yellow bill. The hind toe on their foot is only a tiny bump, giving the bird its scientific name Rissa tridactyla, meaning “three-toed” (instead of four on each foot). In the winter they acquire a dark grey smudge behind their eyes and develop a grey hind-neck collar. Their name is derived from its call which sounds like a shrill 'kittee-wa-aaake, kitte-wa-aaake'.

The black-legged kittiwake prefers to eat marine invertebrates, plankton, and fish. They like to feed in flocks and catch their food at the surface of the water. They also dive just below the surface of the water to catch their prey, making them one of the few gulls that dives and swims underwater.

This gull is a coastal bird found in the north Pacific, north Atlantic, Scandinavia, and Europe. They breed in large, noisy colonies on cliffs. A typical nest is lined with moss and seaweed and will contain up to two eggs. Breeding and nesting time frame is usually in July to August. Kittiwakes are born white and develop a distinctive black “W” band across the length of their wings as they become a juvenile. As an adult, the black “W” is replaced with a solid gray color and only the tips remain black.

Courtesy of spwickstrom.com

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