Even though king vultures and other New World vultures (family Cathartidae) look like Old World vultures (family Accipitridae), it is believed that New World vultures are actually descendents of storks. They have skeletal, skull and muscle structure similar to storks, as well as some similar behavioral traits. However, they are almost the same size, have the same beak strength and have the same bare head and neck as Old World vultures. The similarity between Old World and New World vultures is a prime example of convergent evolution.
King vultures, as well as all vultures in the family Cathartidae, lack a voice box (a syrinx and the muscles that make it work). They are not completely silent though, they do make very low croaking sounds. They also make noises during breeding, and give warning sounds if anything approaches their nests.
Communication Channels: acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
King vultures are rarely seen in large numbers and several have been sited in a areas where they were previously thought not to exist. It is apparent, however, that human encroachment and habitat loss have had an adverse affect on king vultures. They are listed as Appendix III by CITES.
CITES: appendix iii
IUCN Red List of Threatened Species: least concern
The King Vulture lays one egg, which is creamy white and takes 53-58 days to hatch. At times both parents incubate the egg while at other times it is just the female. Not much is known about why this behavior takes place. They do wander away from the nest as they get older, which might be a defense from being eaten. Apparently they begin to acquire their adult plumage around 18 months which grow slowly and takes about four years to fully grow in. The young remain with their parents for that period of time.
(honoluluzoo.org/king_vulture.htm; Stiles, F. Gary and Alexander, F. Skutch,1989; Del Hoyo, Elliot, Sargutal, et al., 1994)
There are no known adverse affects of king vultures on humans.
As a result of their unique beauty and size, king vultures are an attraction at zoos.
King vultures, as well as other members of the family Cathartidae, play an important role in their ecosystem. These birds are usually the first to find dead animals and immediately begin to dispose of the rotting remains. As are all scavengers, these birds are important in keeping their environment free of dead, decomposing animals; this may also help reduce possible sources of disease.
Ecosystem Impact: biodegradation
King vultures are scavengers. Their only source of food is dead animals. King vultures are not known to kill any animals, not even ones that are obviously sick or ready to die. Unlike other New World vultures (family Cathartidae), king vultures arguably have no sense of smell. They will fly high in the sky watching and waiting for other smaller vultures to get excited about a find, they then swoop down out of the sky to the carrion. They usually end up stealing the carcass from the vulture that found it in the first place. They have more powerful beaks than other vultures, and are able to break through the tough hides of the carrion. It is often necessary for king vultures to make the initial tear through the hide so that other vultures, with less powerful beaks, can feed. Each New World vulture species has a unique part of a carcass that they specialize in eating. King vultures eat the skin and harder parts of tissue from the dead animals.
Animal Foods: carrion
Primary Diet: carnivore (Scavenger )
King vultures are found in the southern part of Mexico and throughout Central and South America to northern Argentina.
Biogeographic Regions: neotropical (Native )
King vultures generally live in undisturbed forest in the lowland tropics. They have been found in savannas and grasslands also, but usually only when there are forests nearby. They can be found at elevations up to 1200 m. Little is known about king vultures in the wild, but it is believed that they live in the emergent layer of the forest, which is the top most part of the trees above the canopy. Their hard to reach preferred habitat could be why we do not know much about them.
Range elevation: 1200 (high) m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest
There is not very much information about king vultures in the wild, including their lifespan. However, there is at least one pair of birds in Paris that have been studied in captivity for over 30 years.
Average lifespan
Status: captivity: 40 years.
The most noticeable difference between king vultures and other vultures is that they are largely covered with white plumage. Their wings are mostly white with black tips. The ruff, flight and tail feathers are gray to black; the black areas have an almost opalescent sheen. Their wingspan is between 180 to 198 cm (71 to 78 inches), and from head to tail they are about 71 to 81 cm (28 to 32 inches). An adult can weigh from 3 kg (6.6lbs) up to more than 4.5 kg (9.9lbs). Their bare head, neck, beak and muttle are red, orange and yellow, with very striking eyes that are straw, white or silver in color. Their beaks have a hooked tip and cutting edges, which are very strong. Their feet are gray. These birds are very striking, especially since most other vultures are all black. There are no differences between the males and females of this species. When they are young, king vultures are covered with white downy feathers.
Range mass: 3000 to 4500 g.
Range length: 71 to 81 cm.
Range wingspan: 180 to 198 cm.
Sexual Dimorphism: sexes alike
Other Physical Features: endothermic ; bilateral symmetry
King vultures and other members of the family Cathartidae do not seem to have many anti-predation adaptations. Their nests are vulnerable to animals that prey opportunistically on young and eggs (such as snakes (suborder Serpentes)). Adults are vulnerable while eating. If a large cat (family Felidae) comes to a carcass and the vulture is full of food then it may have a hard time getting off of the ground and away from danger. They are also vulnerable to attack if they are injured or ill.
There is some controversy, but it is believed that the nest sites of these birds are very smelly for the purpose of scaring off potential predators.
Known Predators:
The courting ritual of Sarcoramphus papa has only been observed in captivity; it is quite an elaborate show. While mating they are known to be very loud, making unique wheezing and snorting sounds. Like most other members of their family, king vultures are most likely monogamous.
King vultures are solitary birds and do not nest in big colonies. They usually breed during the dry season. King vultures do not build nests, rather they lay their eggs in hollows of rotting logs or stumps or crevices in trees. They usually lay only one egg which is incubated by both parents. Juveniles begin to show adult plumage after 18 months.
Breeding season: Mainly in the dry season
Average eggs per season: 1.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average time to hatching: 57 days.
Both male and female king vultures participate in incubation. Young are altricial. Both parents care for the young at times, while at other times, it is just the mother.
Most birds of prey carry their food to their young in their claws, but New World Vultures (family Cathartidae) have a large crop that enables them to carry quite a bit of food in the gut. They then regurgitate the food to feed their young. Young chicks are fed directly from the parent’s beak, but as they get older, the parents regurgitate the food onto the ground for the young to eat.
Parental Investment: no parental involvement; altricial ; pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female)
