Turkey Vulture Migration Project...
The Turkey Vulture (Cathartes aura) is the most widely
distributed, as well as the most abundant, of all scavenging birds of prey. The
species, which occurs only in the new World, can be seen as far north as
southern Canada and as far south as Tierra del Fuego at the southern tip of
South America. Turkey Vultures also occur on many large and small islands
including Vancouver Island, Canada, Cuba and Puerto Rico in the Caribbean Sea,
and the Falkland Islands in the South Atlantic. Six races or subspecies of
Turkey Vultures are recognized by biologists: including septentrionalis
in eastern North America, meridionalis in western North America, aura
in Mexico, parts of the Caribbean and Central America, ruficollis in
southern Central and northern and central South America, jota in South
America and falklandica in southern South America and the Falkland
Islands. The scientific name for Turkey Vulture, Cathartes aura,
translates as “breezy cleanser,” most likely a reflection of its soaring and
scavenging life style.
Scientists consider North American populations of Turkey Vultures to be partial
migrants, in that northern populations of the species migrate, whereas southern
populations, in general, do not. Eastern North American populations of the
species typically migrate no farther south than Florida and Texas. Western
populations travel at least as far as Colombia and Venezuela, and some experts
believe that some western birds may travel as far south as Brazil and
Argentina. Millions of migrating Turkey Vultures have been counted annually at
migration watch sites in Mexico, Costa Rica, and Panama.
As scientists we are interested in learning more about the movement ecology of
this extremely successful raptor, which seems to have one of the most flexible
of all avian migration systems. Earlier reports from northern South America
suggest that northern migrants, which are larger and more massive than local
residents, dominate the latter when they arrive on their wintering grounds in
December each year. The extent to which such dominance affects the breeding
schedules and numbers of southern birds remains unknown, as does the extent to
which individual migrants visit an over-winter in the same location each year.
In the spring of 2003 Hawk Mountain
Sanctuary initiated a long-term study of migration behavior in Turkey
Vultures in an effort to learn more about the extent, causes, and consequences
of their annual journeys. To date scientists at the sanctuary and its
collaborators have placed tiny radio tags monitored by satellite on 21 Turkey
Vultures in an effort to follow their outbound migrations south each autumn and
their return migrations north each spring. Five of the satellite-tracked birds
also had a data logger surgically implanted in their body cavities. The loggers
record both core body temperature and heart rate. Recovering these data loggers
allows us to determine fluctuations in both body temperature and heart rate
associated with day-night cycles and migration activity. The Sanctuary and its
collaborators also have placed red, yellow, or light blue numbered wing tags on
more than one hundred Turkey Vultures in Canada, Venezuela, and the United
States. (If you happen to see one of these
birds please report it to the Sanctuary).
Hawk Mountain scientists also have been surveying the sizes of Turkey Vulture
winter and summer populations in seven eastern United States and British
Columbia, Canada, as well as in Costa Rica, Panama, Venezuela, Argentina, and
the Falkland Islands. Our plan is to lay the ground work for a long-term
monitoring effort that will track regional and continental populations of this
widespread and common scavenger in hopes of avoiding catastrophic declines in
its populations similar to those that have occurred in Old World Vultures in
many parts of Africa and southern Asia.
A second goal of our research is to provide the general public, including school
children, with the ability to track the daily movements and whereabouts of these
important scavengers across North and South America.
Our website was put together by a team of raptor biologists from Hawk Mountain
Sanctuary and the Falcon Research Group in Bow,
Washington, including, David Barber, Mark Prostor, and Don McCall. Their
support for this work reflects both their concern for and deep curiosity of
these remarkable birds. Bud Anderson, director of the Falcon Research Group has
been particularly generous in making this website possible.
Although often maligned, Turkey Vultures are great natural ambassadors and
teachers. This “everywhere bird” is quickly becoming “everyone’s bird,” and
this website will help establish the continental connections these “sanitation
engineers” are bringing about, both ecologically and sociologically.
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