California Condor at San Diego Zoo.
The Critically Endangered California condor is a member of the New World vulture family (Cathartidae), and has an impressive wingspan of just less than three metres. The featherless head and neck are a reddish-orange colour; a few black feathers sprout from the head and there is a ruff of fine, glossy black feathers around the neck. The neck has an inflatable pouch, which is important in courtship. The plumage is black in colour with large white patches under each wing. Males and females are indistinguishable by size or plumage. Juveniles are grey and adult feathers do not replace this down until the age of five to seven months. Sub-adults retain a grey head until they reach maturity at five to seven years of age, when they acquire the full colouration of an adult.
Biology[]
Soaring over large distances on their immense wings, condors search by sight for the carrion upon which they feed. Adults in captivity begin to breed at six to eight years of age, and pairs mate for life, producing one chick every two years. California condors, like many New World vultures engage in an unusual behavior known as 'urohydrosis' in order to keep cool. This involves urinating on their own legs, which takes heat away from their body through evaporation; the cooled blood is then circulated back through the body.
Range and Habitat[]
The California condor was originally widespread throughout North America, but by the 1800s they were restricted to the west coast, from British Columbia to Baja California. In the 1970s only 30 individuals remained, all of which were confined to a small area of California, and on Easter Sunday 1987 the species became Extinct in the Wild when the last individual was taken into captivity. An extensive conservation effort has been undertaken to re-introduce captive-bred condors back into the wilds of California, Arizona and Mexico.
Native to a wide variety of North American habitats, the condor is historically restricted to the Pacific coastline and inland to the Sierras. Inhabits rocky, open scrubland, coniferous forest and oak savannah. Nests have been recorded in rock cavities as well as in large Sequoia trees.
Ecology and Behavior[]
When in flight, the movements of the condor are remarkably graceful. The lack of a large sternum to anchor their correspondingly large flight muscles restricts them to being primarily soarers. The birds flap their wings when taking off from the ground, but after attaining a moderate elevation they largely glide, sometimes going for miles without a single flap of their wings. They have been known to fly up to speeds of 90 km/h (56 mph) and as high as 4,600 m (15,100 ft). They prefer to roost on high perches from which they can launch without any major wing-flapping effort. Often, these birds are seen soaring near rock cliffs, using thermals to aid them in keeping aloft.
The California condor has a long life span, reaching up to 60 years. If it survives to adulthood, the condor has few natural threats other than humans. Because they lack a syrinx, their vocal display is limited to grunts and hisses. Condors bathe frequently and can spend hours a day preening their feathers. Condors also perform urohidrosis, or defecate on their legs, to reduce their body temperature. There is a well-developed social structure within large groups of condors, with competition to determine a pecking order decided by body language, competitive play behavior, and a variety of hisses and grunts. This social hierarchy is displayed especially when the birds feed, with the dominant birds eating before the younger ones.
Diet[]
Wild condors maintain a large home range, often traveling 250 km (160 mi) a day in search of carrion. It is thought that in the early days of its existence as a species, the California condor lived off the carcasses of the "megafauna", which are now extinct in North America. They still prefer to feast on large, terrestrial mammalian carcasses such as deer, goats, sheep, donkeys, horses, pigs, cougars, bears, or cattle. Alternatively, they may feed on the bodies of smaller mammals, such as rabbits, coyotes and aquatic mammals such as whales and California sea lions, or salmon. Bird and reptile carcasses are rarely eaten. Since they do not have a sense of smell, they spot these corpses by looking for other scavengers, like eagles and smaller vultures, the latter of which cannot rip through the tougher hides of these larger animals with the efficiency of the larger condor. They can usually intimidate other scavengers away from the carcass, with the exception of bears, which will ignore them, and golden eagles, which will fight a condor over a kill or a carcass. In the wild they are intermittent eaters, often going for between a few days to two weeks without eating, then gorging themselves on 1–1.5 kilograms (2.2–3.3 lb) of meat at once.
Reproduction[]
Condors begin to look for a mate when they reach sexual maturity at the age of six. To attract a prospective mate, the male condor performs a display, in which the male turns his head red and puffs out his neck feathers. He then spreads his wings and slowly approaches the female. If the female lowers her head to accept the male, the condors become mates for life. The pair makes a simple nest in caves or on cliff clefts, especially ones with nearby roosting trees and open spaces for landing. A mated female lays one bluish-white egg every other year. Eggs are laid as early as January to as late as April. The egg weighs about 280 grams (10 oz) and measures from 90 to 120 mm (3.5 to 4.7 in) in length and about 67 mm (2.6 in) in width. If the chick or egg is lost or removed, the parents "double clutch", or lay another egg to take the lost one's place. Researchers and breeders take advantage of this behavior to double the reproductive rate by taking the first egg away for puppet-rearing; this induces the parents to lay a second egg, which the condors are sometimes allowed to raise.
The eggs hatch after 53 to 60 days of incubation by both parents. Chicks are born with their eyes open and sometimes can take up to a week to leave the shell completely. The young are covered with a grayish down until they are almost as large as their parents. They are able to fly after five to six months, but continue to roost and forage with their parents until they are in their second year, at which point the parents typically turn their energies to a new nest. Ravens are the main predatory threat to condor eggs, while golden eagles and bears are potential predators of condor offspring.
Gallery[]
