Wednesday, 17 August 2011

Great Northern Loon


This species, like all divers, is a specialist fish-eater, catching its prey underwater, diving as deep as 200 feet (60 m). Freshwater diets consist of pike, perch, sunfish, trout, and bass; salt-water diets consist of rock fish, flounder, sea trout, and herring.

The bird needs a long distance to gain momentum for take-off, and is ungainly on landing. Its clumsiness on land is due to the legs being positioned at the rear of the body: this is ideal for diving but not well-suited for walking. When the birds land on water, they skim along on their bellies to slow down, rather than on their feet, as these are set too far back. The loon swims gracefully on the surface, dives as well as any flying bird, and flies competently for hundreds of kilometers in migration. It flies with its neck outstretched, usually calling a particular tremolo that can be used to identify a flying loon. Its call has been alternately called "haunting," "beautiful," "thrilling," "mystical" and "enchanting."

Great Northern Loon nests are usually placed on islands, where ground-based predators cannot normally access them. However, eggs and nestlings have been taken by gulls, corvids, raccoons, skunks, minks, foxes, snapping turtles and large fish. Adults are not regularly preyed upon, but have been taken by sea otters (when wintering) and bald eagles. Ospreys have been observed harassing divers, more likely out of kleptoparasitism than predation. When approached by a predator of either its nest or itself, divers sometimes attack the predator by rushing at it and attempting to impale it through the abdomen or the back of the head or neck.