Cathartidae New World Vultures
Version: 1.0 — Published March 4, 2020
Introduction
From the buoyant, tilting dihedrals of turkey vultures to the enormous flat and stable wings of Earth’s largest soaring birds, the condors, these scavengers reveal their mastery of an energy-efficient lifestyle. All can traverse hundreds of kilometers without flapping once. So adept at finding the smallest currents in the air to stay aloft, they often seem hesitant to land. They may perch near a carcass for a day or more to be sure the animal is indeed dead and there are no predators waiting to take advantage of their relatively poor take-off abilities. Some species forage at low altitude and others from a higher vantage, depending on whether they rely primarily on vision or scent to spot dead animals.
Habitat
New World vultures range across all the habitats in their extensive Western Hemisphere distribution, from tropical rainforest to the high peaks of the Andes, tidal flats to desert canyons, grasslands, and savanna.
Diet and Foraging
Cathartids are adapted to scavenging on dead vertebrates. Larger species feed on larger animals, as they are both dominant at carcasses and powerful enough to break into thicker skin. Coragyps will occasionally kill helpless prey such as lizards, insects, newborn livestock, bird nestlings, and hatchling sea turtles. Sarcoram phus and Cathartes species have excellent senses of smell, often locating dead animals through thick vegetation. The others rely on keen vision to find food.
Breeding
Cathartids appear to be monogamous with biparental care, though surprisingly little is known about the breeding biology of these birds. Indeed, the breeding of one South American species has never been described, and it is very poorly known for others. What we know of the northern species indicates that cathartids never make a nest and that they are quite variable in the sites they choose. Condor nests are generally inaccessible to mammalian predators, but the smaller vultures sometimes nest in surprisingly exposed situations, including caves, cliff ledges, holes in large trees, old nests of other raptors, and on the ground in rock crevices, beside logs, and underneath bushes. Larger species lay a single egg, and smaller species typically lay 2 eggs. After an incubation period of 40 to 55 days (longer in condors), the downy chicks hatch and are fed regurgitated food until they can fly—up to six months in condors—but the young are still tended by their parents for months later. Both parents, where known, incubate the eggs, brood chicks, and provision the young.
Conservation Status
Two cathartid species (29%) are of conservation concern, both condors (1 NT, 1 CR). The critically endangered California Condor Gymnogyps californianus has been the subject of intensive management; in the 1980’s, the total population was reduced to 22 individuals in the wild. All were taken into captivity for a breeding program. Birds raised from this program are now re-established in the wild, and the population is slowly recovering. This species was often shot in the past, but the major remaining threat to this species is lead poisoning from bullets left in deer carcasses. The Andean Condor Vultur gryphus faces similar threats in South America.
Systematics History
While superficially similar to the Old World vultures, the cathartids are only distantly related to them, these groups representing a classic case of convergence on a similar body type from shared ecology. The taxonomic history of this group has been contentious. Early biochemical and DNA-DNA hybridization studies suggested that Cathartidae is sister to Ciconiidae (Sibley & Ahlquist 1990), but this vulture-stork relationship has been refuted by later studies based on DNA sequences (Wink et al. 1996, Fain & Houde 2004, Ericson et al. 2006a, Griffiths et al. 2007, Hackett et al. 2008, McCormack et al. 2013, Jarvis et al. 2014). These more recent analyses strongly suggest that Cathartidae falls instead within a group that includes Coraciiformes, Piciformes, Strigiformes, and Accipitriformes. Several recent large-scale analyses (Hackett et al. 2008, McCormack et al. 2013, Jarvis et al. 2014) place Cathartidae as sister to Accipitriformes. Given the other evidence for broader affinities elsewhere, we have retained cathartids in their own order for now.
Conservation Status
Least Concern |
71.4%
|
---|---|
Near Threatened |
0%
|
Vulnerable |
14.3%
|
Endangered |
0%
|
Critically Endangered |
14.3%
|
Extinct in the Wild |
0%
|
Extinct |
0%
|
Not Evaluated |
0%
|
Data Deficient |
0%
|
Unknown |
0%
|
Data provided by IUCN (2023) Red List. More information