Turkey vulture (Cathartes aura)

Birds of Nakusp

This week's column focuses on the turkey vulture (Cathartes aura).

The turkey vulture is typically associated with south-western American deserts. Many people are surprised to learn that turkey vultures are actually quite common here in British Columbia, and their numbers have been growing considerably in recent years. In an article published in Wildlife Afield, (the bi-annual journal of the Biodiversity Centre for Wildlife Studies), a series of maps clearly show this trend. The province has been divided up into many small geographic grids. For the 10-year period 1926-1935, the species had been reported in just eleven of these location grids. Subsequent 10-year periods show that number increasing slowly to 21, 26 and then 29 (in the 1956-1965 period). At this point the increase began to accelerate dramatically. In the 1996-2005 period, turkey vultures were reported in 140 grids.

Historically, the greatest numbers were reported along either side of Georgia Straight between the mainland and Vancouver Island. This population feeds largely by scavenging along shorelines. In the interior, the Okanagan Valley was traditionally their centre of abundance. But even there, the population was somewhat locally distributed, numerous in some places and absent in others. I have seen up to fifteen at one time north of Vernon near Otter Lake. Outside the Okanagan their numbers were even more irregular, with pockets of abundance scattered throughout the southern part of the province. Creston was one such pocket.

Turkey vultures spend most of their day soaring in search of food. Their long broad wings are ideally suited to taking advantage of thermals and other pockets of rising air. Vultures are one of the very few species of birds that possess a sense of smell. Experiments have shown that they can locate carrion even when it is not visible. Turkey vultures can usually be separated from other large soaring birds by two features. They generally hold their wings above the horizontal, giving them a definite V-shaped profile. Also the under surface of their wings is two-toned, the leading half of the wing is black, the trailing half is very pale.

Most turkey vulture nests found in B.C. have been in crevices or small caves on steep rocky outcrops. Usually only one or two eggs are laid. The nesting season is quite long; the eggs require about five weeks to hatch, and the young remain in the nest for a further eight to ten weeks.

Up until the early 1990’s, turkey vultures were almost unheard of in the Arrow Lakes Valley. Since then, however, their occurrence has been steadily increasing. Although I have found no nests, I am confident that they are now breeding in the valley. They have been occurring in small groups in the Edgewood area for at least the last 25 years. Mixed groups of adults and young in late summer are a good indication that they are breeding in that area. Just last week I saw 19 perched together near the Burton bridge. Closer to Nakusp, I see them most frequently in Brouse and around the golf course.

 

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