NEW WORLD VULTURES Cathartidae The New World Vultures, or "cathartid vultures," are the carrion-eating "buzzards" of the New World. They are similar in many ways to the 15 species of Old World Vultures (carrion-eating habits, bare heads, strong bills, incredible powers of flight) but the two groups have evolved separately from different ancestors. Indeed, the two sets of vultures -- New World and Old -- are among the world's best examples of convergent evolution (Houston 1974). There is some evidence that New World Vultures evolved from the stork lineage (DNA hybridization studies by Sibley & Ahlquist 1990, others summarized by AOU 1998), but apparently there is recent biochemical and other research contrary to this theory (e.g., papers presented at 2002 A.O.U. convention; see also Griffiths 1994). For now, I follow the Handbook of the Birds of the World by retaining the family Cathartidae in order Falconiformes.

New World Vultures now range from Canada to Tierra del Fuego, southern South America. Among the seven species are some spectacular and specialized large birds. One of these is the King Vulture (the large birds in the roost at left; the smaller ones are the widespread Black Vulture). King Vultures are scarce across their wide range across the primary forests and savanna of the Neotropics. Adults are primarily white-plumaged with an incredible array of colors on their bare heads and necks; the particular adult at left appears to have a full crop (bare skin in center of breast). Young birds (and there is one above and to the left of the adult) are all-black, including the bare head. It is rare enough to see a King Vulture gliding over the forest from afar, so that when I had this opportunity to photograph these at a roost in southern Brazil, I was so delighted that I crawled through the thick grass to get this shot, subjecting my ankles to an attack of chiggers that still itches incessantly lo this month later.....

The two species of condor are the other headliners among cathartid vultures, and the créme de la créme is the California Condor (right). This wonderful photo of an adult California Condor spreading its wings to the morning sun atop a huge tree on Mt. Pinos was taken in 1969 by Brad Schram. This was back when there were California Condors in the wild; back when I was fortunate enough to see wild condors from Mt. Pinos and several other southern California locales (an excellent resource for the history of California Condor is Wilbur 1978). By 1982, only 21 remained in the world and the decision was made to capture them all before they went extinct. The last wild condor was netted in April 1987 for an intensive attempt at captive breeding (after research on breeding Andean Condors Vultur gryphus had occurred). Fortunately, this massive effort -- the most expensive and complex effort to save a species ever undertaken -- has been successful to date. The first captive-born condors were released back into the wild in 1992 near the Mt. Pinos area of southern California, and by 1998 the world population (including captive birds) was 145.

Efforts to re-introduce the condor in its native range expanded to my home county -- Monterey County -- in Dec 1997 & Jan 1999, when a dozen young birds were released. Some have not fared well and had to be recaptured, but others are still ranging widely. Just yesterday (this is written 5 Sep 1999), as Rita & I were driving up the Big Sur coast, we came upon a circling flock of a dozen Turkey Vultures over a wilderness beach. And with those vultures was a huge young condor, mastering the wind-currents on huge square-ended wings! We pulled over, watched it land on a cliff-edge and peer down to the hidden beach below, and then glide down for what we presume was a meal on a washed-up seal or porpoise carcass (it bore a wing tag showing #74; other youngsters have been watched by researchers recently supplementing their diet with "wild" food rather than the still-born calves that are otherwise set out for them). Considering that the first California Condors described to science by British naturalist George Vancouver way back in 1792 were foraging on dead whales on the shores of Monterey Bay, it was astonishingly wonderful to watch a re-introduced "wild" condor foraging along the wild Big Sur coast!  [More information on the Monterey County condors is at my "Condors in Monterey County" web page and on the Ventana Wilderness Society's website, a non-profit organization that funds this project, successfully re-introduced Bald Eagles to the central California coast, and operates the Big Sur Ornithology Lab. I recommend everyone to join this great organization. Of course, such re-introduced birds are not now "countable" for "listers," but if and when they produce wild young from wild nests, they will be.....]

The California Condor photo above illustrates one typical cathartid vulture behavior, wing-sunning: many New World Vultures spend substantial time spreading their wings -- often early in the morning -- which both serves thermoregulatory functions and brings the plumage into good condition. Vultures tend to forage most of the day, riding thermal to thermal but searching for recently-dead meat over a wide range, but return to communal roosts at night. The two Turkey Vultures (left) are at such a communal roost in central California, enjoying the morning sun on a large dead tree that has also seen use as an Acorn Woodpecker granary tree. You may be able to see one of the features that separates New World Vultures from Old World Vultures in this shot: cathartid vultures lack any internal separation in the nostrils, meaning that you can "see right through" the nostrils on the bill to the scenery behind. [The other obvious difference in morphology is the lack of a functional hind toe in cathartids; Houston 1994.]

The New World Vultures are fascinating not only for their stork ancestry and their special adaptations to eating carrion, but for the specialization and codependency of species within this family. The huge condors [California Condor in North America and Andean Condor in western South America], plus the magnificent King Vulture of the Neotropics, might be most prized by bird-watchers, but none of these could exist without contemporaneous small vultures of the genus Cathartes. Only these small vultures have a highly-developed sense of smell (ranking them with kiwis and some petrels in this ability). As dramatically shown in the BBC's video series "Life of Birds with David Attenborough", Turkey Vultures have a remarkable ability to locate recently-dead mammals using nothing but their sense of smell. This ability is shared by the Lesser Yellow-headed and Greater Yellow-headed vultures of the Neotropics (C. burrovianus and C. melambrotus, residents, respectively, of South American savanna and of primary forests). John James Audubon's experiments to the contrary were poorly-designed. Audubon used badly rotting corpses -- which vultures ignore, possibly because of the risk of lethal bacteria -- rather than freshly-killed beasts which vultures will quickly find and consume. The big vultures (King and the condors), with great eye-sight but poor smell, rely primarily on the small vultures to find carrion. The big bruisers then "take-over" the carcass for their fill, but at the same time specialize on skin, tendons, and other tough meat less readily eaten by the small cousins. [Black Vultures also lack a good sense of smell, but feed more on easily-found offal, such as dead fish on shorelines or at man-made dumps.]

I consider the photo below one of my rarest shots: it shows three species of small vultures lined up on a fence, a mixed grouping only rarely encountered (I've seen it only this once). From left to right are a Lesser Yellow-headed Vulture, a Black Vulture, and then two Turkey Vultures.

This shot was taken in the Pantanal of Brazil where the resident Turkey Vultures have a conspicuous white patch on the nape, quite different from the highly-migratory red-headed and red-naped North American birds. It could be that when all is said and done with DNA-DNA and other biochemical studies, what we now know as the "Turkey Vulture" is comprised of two or more separate species (Houston 1994).

Photos: The roost of King and Black vultures Sarcoramphus papa and Coragyps atratus was taken in the Serra das Araras, Mato Grosso, Brazil, on 4 Aug 1999; this particular roost contained ten King Vultures and dozens of Blacks. The adult California Condor Gymnogyps californianus photo is by Brad Schram from Mt. Pinos, California, 16 Sep 1969 (and used only by permission). The Turkey Vultures Cathartes aura were roosting in Robinson Canyon, Monterey Co., California, on 23 Apr 1995. And the three species of vultures were aligned on a fenceline in the Pantanal of Mato Grosso, Brazil, in Aug 1999. All photos © D. Roberson except the condor is © Brad Schram; all rights reserved.

Bibliographic note

There is no "family book" per se, but an excellent introduction to this family, incorporated the more recent research and entertainingly written, is in Houston (1994).

Other literature cited:

American Ornithologists' Union. 1998. Check-list of North American Birds. 7th ed. A.O.U.,  Washington, D. C.

Griffiths, C. 1994. Monophyly of the Falconiformes based on syringeal morphology. Auk 111:787-805.

Houston, D. C. 1994. Family Cathartidae (New World Vultures), pp. 24-41 in del Hoyo, J., A. Elliott, & J. Sargatal, eds. Handbook of the Birds of the World. Vol. 2, Lynx Edicions, Barcelona.

Sibley, C. G., and J. E. Ahlquist. 1990. Phylogeny and Classification of Birds: A Study in Molecular Evolution. Yale Univ. Press, New Haven, CT.

Wilbur, S. R. 1978. The California Condor 1966-76: A Look at its Past and Future. North America Fauna 72. U. S. Fish & Wildlife Serv., Washington, D.C.




Page created 5 Sep 1999, updated 1 Mar 2003