The natural world: Turkey vultures

On misty mornings, turkey vultures can be seen throughout Sonoma County, lined up on fence posts with their wide wings hung out to dry in the warming sun.

Once the thermals start rising, so do the birds as they search for dead things under the forest canopy, in meadows and on highways. A favorite turkey vulture picnic site is at the confluence of Austin Creek and Russian River in Guerneville.

Few creatures have their sense of smell, which is so acute they can detect the smell of decaying flesh wafting off carrion a mile away. Once a dead animal is located, they dip into its soft parts while waiting for the rest of their meal to ripen. The more putrid it gets, the better.

Turkey vultures have immune systems to die for, never succumbing to botulism, anthrax, cholera and salmonella. But after gorging, the heavy birds must take off into the wind and sometimes have trouble gaining enough loft to lift themselves above the traffic.

They may be solitary or congregate in spiraling, soaring flocks called 'kettles,' but commonly tuck in together on a safe perch when the sun goes down. Nests are scraped out in leaf litter or soil, as far from people as possible. Turkey vultures lay one to three eggs that incubate in roosts for 28 to 40 days.

When wondering whether you're looking at a vulture, a hawk or an eagle, remember that vultures soar more than flap, they're bigger than a red-tail hawk but smaller than an eagle, and they hold their wings in a V while tilting from side to side.

They're dark brown, not black, and have calls that have been described as rudimentary grunts.

Their heads are absent of feathers so they're less likely to carry bacteria when lifting their heads out of body cavities.

The adult's head flushes a brighter red during courting season, when pairs perform a 'follow flight,' with one bird leading the other through twists, turns and flapping flights for up to three hours.

Partners in Flight estimates a global breeding population of 18 million, nevertheless turkey vultures remain a protected species.