California Condor
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 Immature California Condor
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| Gymnogyps californianus Shaw, 1797 |
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The California Condor, Gymnogyps californianus is a species of bird in one of the vulture families. It is the largest flying land bird in North America.
This condor nowadays only inhabits the western coastal mountains of the United States. Although it is primarily a scavenger, feeding on carrion, this species belongs to the New World vulture family Cathartidae, related to storks and not closely related to Old World vultures, which are in the family Accipitridae along with hawks, eagles and kites.
[edit] Appearance
California Condors can reach wingspans of 2.8 m (over 9 ft) and can weigh up to 11.4 kg (25 lb) [1], making them one of the largest North American birds. They are outweighed only by the Trumpeter Swan (Cygnus buccinator, up to 17.2 kg/38 lb), and Mute Swan (Cygnus olor, up to at least 14.3 kg/31½ lb. generally heavier than C. buccinator), an introduced species. The California Condor does have the largest wingspan, the runner-up being the American White Pelican (Pelecanus erythrorhynchos, 244-290 cm/96-114 in). The wingspan of this species is so huge that the untrained observer has occasionally mistaken a condor for a small, distant airplane. Measurements are usually taken from specimens reared in captivity. The Vinny Segretario Vulture Society is helping to ensure the safety of the California Condors.
The adult plumage is of a uniform black, with the exception of a frill of black feathers nearly surrounding the base of the neck and, especially in the male, large triangular patches or bands of white on the underside of the wings which do not appear until the completion of the first moulting. As an adaptation for hygiene, the head and neck have few feathers (see below photo), exposing the skin to the sterilizing effects of dehydration and ultraviolet light at high altitudes, and are meticulously kept clean by the bird. The skin of the head and neck is capable of flushing noticeably in response to emotional state, which serves to communicate between individuals.
The middle toe is greatly elongated, and the hinder one but slightly developed, while the talons of all the toes are comparatively straight and blunt. The feet are thus more adapted to walking as in their relatives the storks, and of little use as weapons or organs of prehension as in birds of prey and Old World vultures. The female, contrary to the usual rule among birds of prey, is smaller than the male.
[edit] Behavior
Sexual maturity and breeding behavior do not appear in the condor until 5 or 6 years of age. They may live for 50 years or more, and mate for life. It deposits one or two bluish-white eggs, weighing about 10 ounces (280 g) and from 3 to 4 inches (75 to 100 mm) in length, during the months of February and March every second year. The egg hatches after 54–58 days of incubation by both parents. If the chick or egg is lost or removed, another egg is laid to take its place. This is called a double clutch. Researchers and breeders take advantage of this behavior to double the reproductive rate by taking the first egg away for hand-rearing, causing the parents to lay a second egg which they are generally allowed to raise.
The young are covered with a grayish down until almost as large as their parents. They are able to fly after six months, but continue to roost and hunt with their parents until age two, when they are displaced by a new clutch. There is a well developed social structure within large groups of condors, with competition to determine a 'pecking order' by body language, competitive play behavior, and a wide variety of vocalizations, even though the condor has no voice box.
On wing the movements of the condor, as it wheels in majestic circles, are remarkably graceful. The lack of a large sternum to anchor correspondingly large flight muscles identifies them physiologically as primarily soarers. The birds flap their wings on rising from the ground, but after attaining a moderate elevation they seem to sail on the air. Charles Darwin commented on having watched them for half an hour without once observing a flap of their wings{[citation needed]. They prefer to roost on high places from where they can launch without major wing-flapping effort. Oftentimes, these birds are seen soaring near rock cliffs, using the heat thermals to aid them with rising in the air.
Wild condors inhabit large territories, often traveling 250 km (150 miles ) a day in search of carrion. They prefer large carcasses such as deer or cattle which they spot by looking for other scavengers, who cannot rip through the tougher hides of these larger animals with the efficiency of the larger condor. In the wild they are intermittent eaters, often going for a few days without eating, then gorging themselves on several pounds at once, sometimes to the point of being unable to lift off the ground.
[edit] Status and conservation
At the time of human settlement of the Americas, the California Condor was more widespread; numerous remains of, and cultural artifacts associated with California Condors attest that Native Americans have always held it in high regard (especially after Merriam's Teratorn, apparently the original "thunderbird", had become extinct). However, climate changes associated with the end of the last ice age and the extinction of the Pleistocene megafauna led to a subsequent reduction in range and population. Prehistorically, California Condors are known from Arizona (Miller, 1960), Nevada (Miller, 1931), New Mexico (Wetmore, 1931, 1932), and Texas (Wetmore & Friedmann, 1938); see also below.
The condor's fickle mating habits and resulting low birth rate combined with a late age of sexual maturity make the bird vulnerable to loss of population. In earlier times, cattle drivers observed condors feeding on the dead young of cattle, and assumed that the birds killed the cattle - a fallacy which led to their extinction in some parts of the western United States. This fallacy was so deeply ingrained that the reintroduction of condors to the Grand Canyon was challenged in court by distant cattle ranchers, who had been erroneously taught by their parents that the bird was a predator of calves and lambs. This delayed their introduction pending a court decision favorable to their reintroduction.
The California Condor remains in danger of extinction; by 1982, only 22 individuals were left alive, all in captivity (The 2006 population stands at about 299)[2]. Significant damage to the condor population is attributed to hunting, lead poisoning (from eating animals containing lead shot), DDT poisoning (Kiff et al., 1979), electric power lines and habitat destruction.
Beginning in the 1980s, a captive breeding program was undertaken to try to restore the species. Condors were released in 1991 and 1992 in California, and again in 1996 in Arizona near the Utah border. The condors were also reintroduced into the wild in the Grand Canyon national park. Their numbers are increasing steadily, particularly in the South Rim of the Canyon, where tourists may view these creatures (as they are attracted by the milling crowds of tourists).
Unanticipated deaths among these populations occurred due to contact with Golden Eagles, power lines 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, only two condors have died as a result of contact with power lines. [3] 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 (Thacker, 2006); this lead waste is not as much of a problem for other avian scavengers such as the Turkey Vulture and Common Raven. This problem is expected to be addressed by a requirement that hunters use solid copper bullets when hunting in condor ranges.
In 2003 the first bird fledged in the wild since 1981. In March 2006, a pair of California condors were seen nesting in a hollowed out tree in 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. [4][5]
An image of the California Condor, along with John Muir and Half Dome, appears on the California State quarter that was issued in January 2005.
A Condor chick, #412, wobbled on its legs and took flight from its nest for only the second time in more then 14 years. Steve Thompson, from the Fish and Wildlife Service said "This is a significant event. Each time a condor chick fledges in the wild it brings us that much closer to the goal of the recovery of this great bird."
[edit] Taxonomy
See Sibley-Ahlquist taxonomy for an alternative classification.
The genus Gymnogyps nowadays has a relict distribution. During the Pleistocene, it was more widespread in the Americas. From fossils, the Floridan Gymnogyps kofordi (Early Pleistocene) and Gymnogyps howardae from the Late Pleistocene of Peru have been described. A condor found on Late Pleistocene deposits on Cuba was initially described as Antillovultur varonai, but has been recognized to also belong into Gymnogyps. It even may be a subspecies of the California Condor.
The California Condor of today has no accepted subspecies anymore; although its range has much contracted during the Holocene, the species always had a small and much interbreeding population. However, there is a Late Pleistocene palaeosubspecies, Gymnogyps californianus amplus, which occurred over much of the bird's historical range - even extending into Florida - and was larger, about equal in weight to the Andean Condor, and had a wider bill (Fisher, 1944). As the climate changed during the last ice age, the entire population became smaller until it had evolved into the Gymnogyps californianus californianus of today (Howard, 1947, 1962; see also Black Vulture).
[edit] References
- BirdLife International (2006). Gymnogyps californianus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 4 Sep 2006. Database entry includes justification for why this species is critically endangered.
- Fisher, Harvey L. (1944): The skulls of the Cathartid vultures. Condor 46(6): 272-296. PDF fulltext
- Howard, Hildegarde (1947): A preliminary survey of trends in avian evolution from Pleistocene to recent time. Condor 49(1): 10-13. PDF fulltext
- Howard, Hildegarde (1962): Bird Remains from a Prehistoric Cave Deposit in Grant County, New Mexico. Condor 64(3): 241-242. PDF fulltext
- Kiff, L. F.; Peakall, D. B. & Wilbur, S. R. (1979): Recent Changes in California Condor Eggshells. Condor 81(2): 166-172. PDF fulltext
- Lesson, René-Primevère (1842): [Description of genus Gymnogyps]. L'Echo du monde savant ser. 2 6(44): col. 1037.
- Miller, Loye (1931): The California Condor in Nevada. Condor 33(1): 32. PDF fulltext
- Miller, Loye (1960): Condor Remains from Rampart Cave, Arizona. Condor 62(1): 70 PDF fulltext
- Thacker, Paul D. (2006): Condors are shot full of lead. Environmental Science & Technology 40(19): 5826. HTML fulltext
- Wetmore, Alexander (1931): The California Condor in New Mexico. Condor 33(2): 76-77. PDF fulltext
- Wetmore, Alexander (1932): Additional Records of Birds from Cavern Deposits in New Mexico. Condor 34(3): 141-142. PDF fulltext
- Wetmore, Alexander & Friedmann, Herbert (1938): The California Condor in Texas. Condor 35(1): 37-38 PDF fulltext
[edit] External links
- BirdLife Species Factsheet
- 7" x 4.6" 71.8 KB Condor JPEG provided by the U.S. Fish & Wildlife Service
- Ventana Wildlife Society Retrieved 2006-OCT-7
- Peregrine Fund Retrieved 2006-OCT-7
