California condor

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California condor
Temporal range: 2.5–0 
Ma
↓
Early Pleistocene – Holocene
Condor #534 soaring over the Grand Canyon, U.S.

Critically Endangered (IUCN 3.1)[1]
CITES Appendix I (CITES)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Avialae
Order: Accipitriformes
Family: Cathartidae
Genus: Gymnogyps
Species:
G. californianus
Binomial name
Gymnogyps californianus
(Shaw, 1797)
Range map of California condor:
  Extant (resident)
  Possibly extinct
Synonyms

Genus-level:

  • Antillovultur Arredondo, 1971
  • Pseudogryphus Ridgway, 1874[3]

Species-level:

  • Vultur californianus Shaw, 1797[4]

The California condor (Gymnogyps californianus) is a

International Union for the Conservation of Nature as Critically Endangered, and similarly considered Critically Imperiled by NatureServe.[5]

The

longest-living birds, with a lifespan of up to 60 years.[6]

traditional myths
.

Taxonomy

Frederick Polydore Nodder's illustration accompanying George Shaw's 1797 species description

The California condor was described by English naturalist

Quechua word kuntur.[13]

A California condor skull

The exact

Ciconiiformes and instead placed them in Incertae sedis, but notes that a move to Falconiformes or Cathartiformes is possible.[14]

As of the 51st Supplement (2010) of the American Ornithologists' Union, the California condor is in the family

Cathartidae of the order Cathartiformes.[18]

Evolutionary history

Fossil of the extinct species Gymnogyps amplus from the La Brea Tar Pits

The

Gymnogyps howardae from the Late Pleistocene have been described.[19] A condor found in Late Pleistocene deposits on Cuba was initially described as Antillovultur varonai, but has since been recognized as another member of Gymnogyps, Gymnogyps varonai. It may even have derived from a founder population of California condors.[20]

The California condor is the sole surviving member of Gymnogyps and has no accepted subspecies. However, there is a Late Pleistocene form that is sometimes regarded as a palaeosubspecies, Gymnogyps californianus amplus. Opinions are mixed, regarding the classification of the form as either a chronospecies or a separate species, Gymnogyps amplus.[21] Gymnogyps amplus occurred over much of the bird's historical range – even extending into Florida – but was larger, having about the same weight as the Andean condor. This bird also had a wider bill.[22] As the climate changed during the last ice age, the entire population became smaller until it had evolved into the Gymnogyps californianus of today,[23][24] although more recent studies by Syverson question that theory.[21]

Description

An adult in flight. Tracking tags can be seen on both wings.

The adult California condor is a uniform black with the exception of large triangular patches or bands of white on the underside of the wings. It has gray legs and feet, an ivory-colored bill, a frill of black feathers surrounding the base of the neck, and brownish red eyes.[25] The juvenile is mostly a mottled dark brown with blackish coloration on the head. It has mottled gray instead of white on the underside of its flight feathers.[26]

The condor's head has little to no feathers, which helps keep it clean when feeding on carrion.[27] The skin of the head and neck is capable of flushing noticeably in response to emotional state.[28] The skin color varies from yellowish to a glowing reddish-orange.[25] The birds do not have true syringeal vocalizations. They can make a few hissing or grunting sounds only heard when very close.[29]

The upper body and head

The female condor is smaller than the male, an exception to the rule among

birds of prey (the related Andean condor is another exception). Overall length ranges from 109 to 140 cm (43 to 55 in) and wingspan from 2.49 to 3 m (8 ft 2 in to 9 ft 10 in). Their weight ranges from 7 to 14.1 kg (15 to 31 lb), with estimations of average weight ranging from 8 to 9 kg (18 to 20 lb).[26][30] Wingspans of up to 3.4 m (11 ft) have been reported but no wingspan over 3.05 m (10.0 ft) has been verified.[31]
Most measurements are from birds raised in captivity, so it is difficult to determine if major differences exist between wild and captive condors.

California condors have the largest wingspan of any North American bird. They are surpassed in both body length and weight only by the trumpeter swan and the introduced mute swan. The American white pelican and whooping crane also have longer bodies than the condor. Condors are so large that they can be mistaken for a small, distant airplane, which possibly occurs more often than that they are mistaken for other bird species.[32]

The middle toe of the California condor's foot is greatly elongated, and the hind toe is only slightly developed. The

prehension
.

Historic range

California oak savanna on the east flank of Sonoma Mountain

At the time of

American Southwest and West Coast. Faunal remains of condors have been found documented in Arizona,[36] Nevada,[37] New Mexico,[38][39] and Texas.[40] The Lewis and Clark Expedition of the early 19th century reported on their sighting and shooting of California condors near the mouth of the Columbia River.[41][42]

In the 1970s, two Condor Observation Sites were established in the

Sespe Wildlife Area of Los Padres National Forest, and one atop Mount Pinos, "accessible from a dirt road off the highway in from Gorman".[43]

Habitat

The California condor lives in rocky

coniferous forest, and oak savanna.[1] They are often found near cliffs or large trees, which they use as nesting sites. Individual birds have a huge range and have been known to travel up to 250 km (160 mi) in search of carrion
.

There are two sanctuaries chosen because of their prime condor nesting habitat: the Sisquoc Condor Sanctuary in the San Rafael Wilderness[44] and the Sespe Condor Sanctuary in the Los Padres National Forest.

The Los Padres Condor Range and River Protection Act of 1992 expanded existing wilderness by 34,200 hectares (84,400 acres) and designated 127,900 hectares (316,050 acres) of new wilderness that provide habitat for the condor in the Los Padres.

Ecology and behavior

Preening condors

The California condor's large flight muscles are not anchored by a correspondingly large

thermals to aid them in keeping aloft.[46]

The California condor has a long life span, reaching up to 60 years.

body temperature.[28] 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.[48]

Breeding

An adult with a 30-day-old chick in a cave nest near the Hopper Mountain National Wildlife Refuge, California, U.S.

Condors begin to look for a mate when they reach sexual maturity at the age of 6.

egg every other year. Eggs are laid as early as January to as late as April.[49] 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.[50]

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.[28] The young are covered with a grayish down until they are almost as large as their parents. They are able to fly after 5 to 6 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.[25] Ravens are the main predatory threat to condor eggs, while golden eagles and bears
are potential predators of condor offspring.

In 2021, the San Diego Zoo reported having had two unfertilized eggs hatch within its breeding program in 2001 and 2009, producing male young by parthenogenesis as indicated by genetic studies. The mothers had been housed with males and had mated before, but the offspring lacked markers of male paternity and showed all-maternal inheritance, suggesting the specific mechanism of parthenogenesis involved automixis, gametic fusion, or endomitosis.[51][52][53] Earlier evidence of similar parthenogenesis in birds found that among the known examples the embryos died before hatching, unlike these condor chicks. Neither chick lived to sexual maturity, preventing data collection on their reproductive potential.[54]

Feeding

Juveniles feeding

Wild condors maintain a large home range, often traveling 250 km (160 mi) a day in search of carrion.[55] It is thought that in the early days of its existence as a species, the California condor lived off the carcasses of the Pleistocene megafauna, which are largely 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, squirrels,[56] or coyotes, aquatic mammals such as whales and California sea lions, or salmon. Bird and reptile carcasses are rarely eaten. Condors prefer fresh kills, but they also eat decayed food when necessary.[56] Since they do not have a sense of smell,[57] 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.[25] In the wild they are intermittent eaters, often going for between a few days to two weeks without eating,[55] then gorging themselves on 1–1.5 kilograms (2.2–3.3 lb) of meat at once.

Conservation

A juvenile in the Grand Canyon, with its numbered tag prominent.

The California condor conservation project may be one of the most expensive species conservation projects in United States history,[58] costing over $35 million, including $20 million in federal and state funding, since World War II.[59] As of 2007, the annual cost for the condor conservation program was around $2.0 million per year.[59]

Recovery plan

A condor chick being fed by a condor head feeding puppet

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 and that capturing all of the condors would change the species' habits forever, and that the cost was too great.

Easter Sunday 1987, when AC-9, the last wild condor, was captured.[61] At that point, there were only 22 surviving condors, all of them in captivity.[62]
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.

The study and capture of the remaining California condors was made possible through the efforts of Jan Hamber, an ornithologist with the Santa Barbara Museum of Natural History. Hamber personally captured AC-9,[63] the final wild California condor, and her dedication to the bird's conservation led her to compile decades of field notes into the Condor Archives, a searchable database focused on condor biology and conservation.[63]

The captive breeding program, led by the

San Diego Wild Animal Park and Los Angeles Zoo,[64] and with other participating zoos around the country, including the Oklahoma City Zoo and Botanical Garden, 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.

Aside from breeding programs, the Condor Recovery Center at Oakland Zoo treats condors that are ill from lead poisoning.[65]

Large black bird with featherless head and hooked bill
The California condor once numbered only 22 birds, but conservation measures have raised that number to over 500 today.

Reintroduction to 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.[45] California condors were released in 1991 and 1992 in California at Big Sur, Pinnacles National Park and Bitter Creek National Wildlife Refuge and in 1996 at the Vermilion Cliffs release site in Arizona near the Grand Canyon.[26] The Fish and Wildlife Service designated the Arizona condors as an experimental, nonessential animal so they would not affect land regulations or development as ranchers were concerned they could be charged with an offense if any birds were injured on their property after the release.[66] Though the birth rate remains low in the wild, their numbers are increasing steadily through regular releases of captive-reared adolescents.[67]

A USFWS sign at Bitter Creek National Wildlife Refuge showing the site's association with the California Condor Recovery Program

Obstacles to recovery

In modern times, a wide variety of causes have contributed to the California condor's decline. Its low clutch size (one young per nest), combined with a late age of sexual maturity, make the bird vulnerable to artificial population decline. Significant past damage to the condor population has also been attributed to

egg collecting, and habitat destruction. During the California Gold Rush, some condors were even kept as pets.[72] The leading cause of mortality in condor nestlings is the ingestion of trash that is fed to them by their parents.[73]

Premature deaths among condor populations continued to occur due to contact with golden eagles, lead poisoning, and other factors such as power line collisions.[74] 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.[75]

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; lead waste is not as much of a problem for other avian scavengers such as the turkey vulture and common raven.[76] In California, the Ridley-Tree Condor Preservation Act went into effect July 1, 2008, requiring that hunters use non-lead bullets when hunting in the condor's range.[77] Blood lead levels in golden eagles as well as turkey vultures has declined with the implementation of the Ridley-Tree Condor Preservation Act, demonstrating that the legislation has helped reduce other species' lead exposures aside from the California condor.[78][79] There is no comparable anti-lead-bullet legislation in the other states in which the condor resides.

"Over 60 percent of the adult and juvenile deaths (that is, excluding chicks and fledglings) in the wild population have been as a result of lead poisoning" according to Dawn Starin in an article ("Condors or lead ammunition? We can't have both") published by The Ecologist in January 2015.[80] She continues: "Because condors have been known to live past the age of 50, do not breed until they are at least six years old, and raise only one chick every other year, their populations cannot withstand the mortality rates caused by this neurological toxin."[80]

According to

epidemiologist Terra Kelly: "Until all natural food sources are free from lead-based ammunition, lead poisoning will threaten recovery of naturally sustaining populations of condors in the wild."[80] The article also states: "The military doesn't use lead, and if that isn't a huge message I don't know what is."[80][81]

Avian influenza infected and killed condors in the Arizona-Utah flock in 2023.[82]

Population growth

Nesting milestones have been reached by the reintroduced condors. In 2003, the first nestling fledged in the wild since 1981.[83] 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 that a pair of California condors had been seen nesting in Northern California.[84]

In October 2010, the wild condor population reached 100 individuals in its namesake state of California, plus 73 wild condors in Arizona.[67] In November 2011, there were 394 living individuals, 205 of them in the wild[6][7] and the rest in the San Diego Zoo Safari Park, the Santa Barbara Zoo, the Los Angeles Zoo, the Oregon Zoo, and the World Center for Birds of Prey in Boise, Idaho. In May 2012, the number of living individuals had reached 405, with 179 living in captivity.[85] By June 2014, the condor population had reached 439: 225 in the wild and 214 in captivity.[86] Official statistics from the December 2016 USFWS recorded an overall population of 446, of which 276 are wild and 170 are captive.[87] A key milestone was reached in 2015 when more condors were born in the wild than died.[88]

Reintroduction to Mexico

As the Recovery Program achieved milestones, a fifth active release site in Sierra de San Pedro Mártir National Park, Baja California, Mexico, was added to the three release sites in California and the release site in Arizona.[89][90] In early 2007, a California condor laid an egg in Mexico for the first time since at least the 1930s.[91]

In June, 2016, three chicks that were born in Chapultepec Zoo in Mexico City, were flown to Sierra de San Pedro Mártir National Park, Baja California, Mexico.[92] 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.[93]

Expanded range

In 2014, Condor #597, also known as "Lupine", was spotted near Pescadero, a coastal community south of San Francisco.[94] Lupine had been routinely seen at Pinnacles National Park after having been released into the wild at Big Sur the previous year. Younger birds of the central California population are seeking to expand their territory, which could mean that a new range expansion is possible for the more than 60 condors flying free in central California.[95] Also in 2014 the first successful breeding in Utah was reported. A pair of condors that had been released in Arizona, nested in Zion National Park and the hatching of one chick was confirmed.[96] The 1,000th chick since recovery efforts began hatched in Zion in May 2019. The California condor was seen for the first time in nearly 50 years in Sequoia National Park in late May 2020.[97][98]

Pinnacles National Park, a release site

As part of an effort headed by the Yurok tribe to reintroduce the condor to the coastal redwoods of northern California, birds hatched at the Oregon Zoo and the World Center for Birds of Prey were released at Redwood National Park in 2022.[99]

Condor Watch

Zooniverse
icon for Condor Watch

A

Zooniverse, volunteers were asked to examine motion-capture images of California condors associated with release sites managed by the United States Fish and Wildlife Service, National Park Service and Ventana Wildlife Society.[102]
The tasks on the website included identifying tagged condors and marking the distance to feeding sources such as animal carcasses. Biologists can then use this data to deduce which birds are at risk of lead poisoning.

Condor Watch enabled volunteers, or

Audubon Society's Christmas Bird Count, which began in 1900 and the breeding bird survey which began in 1966. McCaffrey (2005) believes this approach not only directly benefits ongoing projects, but will also help train aspiring ornithologists.[103]

Relationship with humans

Condor on California's state quarter

Throughout its historic range, the California condor has been a popular subject of

mythology and an important symbol to Native Americans. Unusually,[104]
this bird takes on different roles in the storytelling of the different tribes.

The

Yokuts people, the condor sometimes ate the moon, causing the lunar cycle, and his wings caused eclipses.[107] The Chumash tribe of Southern California tell that the condor was once a white bird, but it turned black when it flew too close to a fire.[107]

Condor bones have been found in Native American graves,[108] as have condor feather headdresses. Cave paintings of condors have also been discovered.[109] Some tribes ritually killed condors to make ceremonial clothing out of their feathers. Shamans then danced while wearing these to reach the upper and lower spiritual worlds. Whenever a Shaman died, his clothes were said to be cursed,[110] so new clothing had to be made for his successor. Some researchers, such as Noel Snyder, believe that this practice of making ceremonial clothing contributed to the condor's decline.[110]

See also

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Cited texts

Further reading

External links

Wikimedia Commons has media related to Gymnogyps californianus.
Wikispecies has information related to California condor.
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