An eerie event occurred on Woodland Drive as dusk drew near late on a recent chilly afternoon.

Huge turkey vultures soared against the blue sky as long shadows cast by branches of large, old trees darkened the ground below. The big, black birds soon filled branches of two long-dead trees and a huge, healthy pine tree.

The birds’ arrival is nothing new. They have been roosting in the same trees daily for two years.

By the time humans stir mornings, the birds have flown away for a day of searching for roadkill and other carrion.

With wide wing spans, the first birds — somewhat intimidating — glide in and go into a circling pattern as they spot the roosting destinations. They land and perch, their raven girth plainly visible. Others quickly follow the lead.

Todd Schneider, a wildlife biologist with the Georgia Department of Natural Resources, said the birds seem to be attracted to areas with large trees. They also seem to like being near water, particularly lakes and ponds.

“It’s likely that the trees in the neighborhood where they are roosting are large and fairly openly spaced. Roosting sites are probably located relatively close to consistent food sources, such as major roads or highways,” Schneider said.

 However, he added, vultures can easily travel 10 to 20 miles one way to find food.

“Vulture populations have increased quite a bit over the last few decades, probably because there is more roadkill available due to the greater number of roads and number of people traveling on those roads,” said Schneider, whose office is in Forsyth.

The birds most often roost in or along the edge of open forests and woodlots in rural areas.

Schneider has seen a lot of vultures roost in forested areas near large powerline corridors.

“I’m not sure if this is because they prefer these sites or if they’re more visible in these locations. We still don’t know all the reasons why they pick particular roosting sites,” he explained.

See Sunday’s edition for more details.