Biology Reference
In-Depth Information
Species Specific
Q I am curious about the Turkey Vultures that roost in the tall pine trees a block
from our house, right near a cemetery — there is even a sign on the road that says
“Dead End”! I never thought of vultures as particularly social — what are their
mating and nesting habits?
A TurkeyVultures usually forageindividually.Bysplitting up,each birdsniffingoutcar-
casses, one is eventually going to hit the jackpot and others will notice it dropping down
and will join it. In the evening, vultures join together at communal roosts, ranging in size
fromafewbirdstoseveralthousand.Spectaculareveningflights“advertise”theseroosts.
One 15-year study of tagged Turkey Vultures in Wisconsin suggests that they usually
mate for life, but when a bird's mate dies, it does take a new mate. Although they spend
the nesting period together and cooperate closely in incubating eggs and caring for the
young, there's no evidence that a pair migrates or spends winter together.
TurkeyVulturesnestoncliffs,hollowsbeneathfallenlogs,rockoutcrops,caves,aban-
doned buildings, and other places isolated from humans. They don't construct much of
anything in the way of a nest for their (usually) two eggs. Both parents develop brood
patches, a bare spot on their underside that is pressed against the eggs. Both take turns
incubating the eggs, which take over a month (often as long as 40 days) to hatch.
The parents feed their fluffy white chicks the same rotten meat they eat, only in regur-
gitated form. The chicks make their first flights sometime between 60 and 80 days after
hatching. After they leave the nest, they receive little or no care from their parents, but
siblings sometimes stay together for a while. They join communal roosts, keep track of
other birds in order to locate food as they get practice sniffing out the world, but are gen-
erally on their own.
AS SILENT AS THE GRAVE
Turkey Vultures lack a syrinx and the voice-producing muscles associated with it,
so they are essentially always silent. They can make a guttural hiss when agitated, either
by a disturbance at the nest or when two birds are vying for the same part of a carcass.
And nestlings make a characteristic hiss that is almost inaudible while they're still blind
and unable to hold up their heads. By the time they're a week old or so, they make a
specific nestling-hiss when disturbed. This sound has been variously described as a per-
sistent and vigorous wheezing-snoring; a low, throaty, or growling hiss; a snake rattle;
or a roaring wind. The sound volume and quality depend on the age of the nestling, the
intensity ofthehiss,howclose theobserveris,andtheacoustic qualities ofthenestarea.
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