The California Condor is one of the most spectacular and highly endangered birds of the world. The largest of the North American Vultures, it is also currently the largest soaring land bird of the continent. Its wingspread of about 9 feet and body weight of about 19 pounds make it a near twin of the Andean Condor of South America.
The California Condor is a huge black raptor. The species exhibits a variety of subtly different plumages as they progress from juvenile to adult; the main difference are in head coloration and the amount of molting in white areas of upperwings and underwings. Sexes are alike in plumage and size. Adults are overall black, except for large white areas on the underwing coverts and a silvery cast to uppersides of secondaries and greater coverts. Head and swollen neck are orange and the legs are whitish. Juveniles are similar in plumage but their heads and necks are narrower and dusky, and underwing coverts are mottled black and white. Immatures gradually get more white on underwing coverts and heads become thicker and more orangish.
The best field marks are the California Condor’s huge size, very broad wings with deeply slotted primaries and bold white triangles on undersides, and orange to orange-yellow puffy heads of all but juveniles, which are blackish. Wings are held level when soaring and gliding but may be held in a shallow dihedral under some soaring conditions.
Habitat and Prey
At the time of human settlement of the Americas, the California Condor was widespread across North America. However, climate changes associated with the end of the last glacial period and the extinction of the Pleistocene megafauna led to a subsequent reduction in range and population. The species was largely confined to southern California by the mid-twentieth century. The California Condor also occurred in northern Baja California, northern California, Oregon, Washington, and southern British Columbia in the early nineteenth century, with a smattering of nineteenth century reports from Arizona, Nevada, Utah, Wyoming, Colorado, Idaho, Montana, and southern Alberta.
The species’ wide Pleistocene distribution and the diverse habitats occupied by the recent population in California indicate very broad habitat and climatic tolerances. The most important habitat requirement may be adequate food supplies, open-enough habitat that food can be readily found and accessed, and reliable air movements allowing extended soaring flight.
The California Condor feeds almost exclusively on mammalian carrion, although occasional remains of reptiles and birds have been found in nests. No predation on live prey has been documented in the wild California Condor population.
Instances of new pair formation in California Condors have been observed in late fall and early winter. Once formed, pairs stay together on a year-round, multiyear basis. For a period of several weeks prior to egg laying, generally in January and February, pairs visit various alternate nest sites within their nesting territories. 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 February or March. The egg weighs about 10 ounces and measures from 3.5–4.75 inches in length and about 2.6 inches in width. If the chick or egg is lost or removed the parents "double clutch", or lay another egg to take place of the one that was lost. Researchers and breeders take advantage of this behavior to double the reproductive rate by taking the first egg away for hand 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 hatch from their egg. 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 hunt with their parents until they turn two, at which point they are displaced by a new clutch.
True migration is unknown for any population.
In modern times, a wide variety of causes have contributed to the condor's decline. Its exacting mating habits and resulting low birth rate, combined with a late age of sexual maturity, make the bird vulnerable to loss of population. Significant damage to the condor population is also attributed to poaching, especially for museum specimens, lead poisoning (from eating animals containing lead shot), DDT poisoning, electric power lines, egg collecting, and habitat destruction. During the California Gold Rush, some condors were even kept as pets.
In addition to this, cattle ranchers who observed condors feeding on the dead young of their cattle assumed that the birds killed the cattle. This fallacy led to the condor's extirpation in some parts of the western United States. This belief was so deeply ingrained that some cattle ranchers, who mistakenly believed that the bird hunted calves and lambs, challenged the reintroduction of California Condors to the Grand Canyon.
Unanticipated deaths among recent condor populations occurred due to contact with Golden Eagles, power lines, wind turbines and other factors such as lead poisoning. Since 1994, captive-bred California Condors have been trained to avoid power lines and people. Since the implementation of this aversion-conditioning program, the number of condor deaths due to power lines has greatly decreased. Lead poisoning due to fragmented lead bullets in large game waste is a particularly big problem for condors due to their extremely strong digestive juices; this lead waste is not as much of a problem for other avian scavengers such as the Turkey Vulture and Common Raven. The Ridley-Tree Condor Preservation Act, a bill that went into effect July 1, 2008 that requires that hunters use non-lead bullets when hunting in the condor’s range, has addressed this problem in California.
As the condor's population continued to decline, discussion began about starting a captive breeding program for the birds. Opponents to this plan argued that the condors had the right to freedom, that capturing all of the condors would change the species' habits forever, and that the cost was too great. However, the project received the approval of the United States government, and the capture of the remaining wild condors was completed on Easter Sunday 1987, when AC-9, the last wild condor, was captured. There were only 22 condors in existence, all in captivity.
The goal of the California Condor Recovery Plan was to establish two geographically separate populations, one in California and the other in Arizona, each with 150 birds and at least 15 breeding pairs. As the Recovery Program works toward this goal the number of release sites has grown. There are three active release sites in California, one in Arizona and one in Baja, Mexico.
The captive breeding program, led by the San Diego Wild Animal Park and Los Angeles Zoo, got off to a slow start due to the condor's mating habits. However, utilizing the bird's ability to double clutch, biologists began removing the first egg from the nest and raising it with puppets, allowing the parents to lay another egg.
As the number of condors grew, attention began to focus on releasing some back into the wild. In 1988, the United States Fish and Wildlife Service began a reintroduction experiment involving the release of captive Andean Condors into the wild in California. Only females were released, to eliminate the possibility of accidentally introducing a South American species into the United States. The experiment was a success, and all the Andean Condors were recaptured and re-released in South America. California Condors were released in 1991 and 1992 in California, and again in 1996 in Arizona near the Grand Canyon. Though the birth rate remains low in the wild, their numbers began increasing steadily through regular releases of captive-reared adolescents.
The California Condor conservation project is the most expensive species conservation project in United States history, costing over $35 million, including $20 million in federal and state funding, since World War II. However, nesting milestones have been recently reached by the reintroduced condors. In 2003, the first nestling fledged in the wild since 1981. In March 2006, a pair of California Condors, released by Ventana Wildlife Society, attempted to nest in a hollow tree near Big Sur, California. This was the first time in more than 100 years in which a pair of California Condors had been seen nesting in Northern California. As of August 2010 there are 384 individuals living, including 188 in the wild and the rest in the San Diego Wild Animal Park, the Los Angeles Zoo, the Oregon Zoo, and the World Center for Birds of Prey in Boise, Idaho. As of October 2010, the wild condor population in its name state of California reached individuals, and 73 wild condors in Arizona.
As the Recovery Program achieved milestones a third active release site in Sierra de San Pedro Mártir National Park, Baja, Mexico, was added to the two release sites in California (Pinnacles National Monument and Bitter Creek National Wildlife Refuge and the Grand Canyon release site in Arizona. In early 2007, a California condor laid an egg in Mexico for the first time since at least the 1930s. The population of the condors has risen due to these wild and also captive nestings. In the spring of 2009, a second wild chick was born in the Sierra de San Pedro Mártir National Park and was named Inyaa (“Sun” in the Kiliwa language) by local environmentalists