Socorro dove | |
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Prize-winning animal of the German Bird Association. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Columbiformes |
Family: | Columbidae |
Genus: | Zenaida |
Species: | Z. graysoni |
Binomial name | |
Zenaida graysoni (Lawrence, 1871) | |
Synonyms | |
Zenaida macroura graysoni |
The Socorro dove or Grayson's dove (Zenaida graysoni) is a dove species which is extinct in the wild. It was endemic to Socorro Island in the Revillagigedo Islands off the west coast of Mexico. The last sighting in its natural habitat was in 1972 and it survives only in captivity. A reintroduction program is being prepared. [2] [3]
It is a close relative of the mourning and eared doves, particularly the former, [4] and was at one time considered a subspecies. In captivity, it hybridizes with the former and almost all privately owned birds as well as several of the captive breeding program birds are known or strongly suspected to be hybrids. These are excluded from the reintroduction program as there is evidence of unique adaptations in the Socorro species. The scientific name commemorates Zénaïde Laetitia Julie Bonaparte and the American ornithologist and artist Andrew Jackson Grayson.
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Cladogram showing the positions of the doves in the genus Zenaida . [5] |
The Socorro dove is [3] a medium-sized, principally terrestrial dove with long legs for a zenaida dove. It is 26.5–34 cm (10.4–13.4 in) long and weighs 190 g (6.7 oz) on average. In overall color pattern, it agrees with its relatives. It is considered to be a stronger-colored insular representative of the mourning dove. The male is deep cinnamon on its head and underparts, with an ear streak like its relatives. The nape is blue-grey and the neck has an iridescent pink patch, most prominent after moult. The upperparts are rufous brown. Female and juvenile coloration is slightly duller. The most conspicuous differences from the mourning dove, darker coloration and more well-developed feet, were useful amid the dark lava rock and the shady forests of its island home, where native mammalian predators were absent but constant threats from red-tailed hawks and great frigatebirds were present. [6] The advertising call begins with a disyllabic coo, followed by three single calls, and ends with another disyllabic coo: "Coo-oo, OO, OO, OO, Coo-oo". Each of these 5 elements takes a little less than one second.[ citation needed ]
The arid and fairly barren Clarión Island, some 400 km (250 mi) west of Socorro, has an endemic subspecies of the mourning dove, Zenaida macroura clarionensis. These birds are roughly intermediate in appearance between the Socorro dove and the mainland mourning doves. It is highly likely that they represent a later colonization by mourning doves (rather than earlier stock), which evolved its phenotype independently from but in parallel with the Socorro birds. [6] This would mean that predation by great frigatebirds is significant enough to select towards a cryptic darkening of the plumage, as these are the only predators of Z. m. clarionensis. On a semidesert island such as Clarión, birds would be expected to evolve towards lighter plumage, to better withstand the heat and lack of reliable freshwater sources, in accordance with Gloger's Rule.[ citation needed ]
The upper elevation limit of the doves is 950 m. [1]
There is marked behavioral difference to the mourning dove. When Andrew Jackson Grayson discussed the species, he called it the "solitary dove" because he never saw more than one male and one female together. The doves, particularly the adult males, chase away their young as soon as these can fend for their own and the partners split for the time being. This too is believed to be in adaptation to the former dominance of aerial predators, lest local concentrations of birds, let alone young, inexperienced ones, would present easy targets for the hawks. Typical of many birds on islands lacking mammals, Socorro doves also show little fear of humans or introduced predators, including cats, which proved a major factor in its extirpation. [3]
The last habitat in which this dove was found is the low seasonally humid forest above 500 m ASL. [2] Before the introduction of cats, it seasonally descended into the lowlands where it was "common" in March 1953 for example. It may be that this coincided with the peak of the breeding season, when many birds had dependent young and dispersed widely to gather more varied food. This was the case in the Socorro mockingbird, the other mid-sized native landbird of Socorro, which apparently has very similar habitat preferences. [6]
Its last refuge was dominated by endemic Guettarda insularis , Ilex socorroensis and Sideroxylon socorrense , as well as black cherry (Prunus serotina), [6] [7] Ficus cotinifolia fig trees and Psidium socorrense guavas, apparently all native on Socorro. At least at the time of the last record, it seemed to be dependent on intact understorey of Euphorbiaceae (spurges and relatives) [7] and ferns, maybe because cats hunt less efficiently in the dense foliage. It is frugivorous and, as is often the case in Columbidae, might have played an important role in the reproduction of the trees which dominate its habitat. One of these (S. socorrense) is classified as vulnerable by the IUCN. [8] In particular, it was found to associate with the fig trees. [2] [6] [7]
Virtually nothing is known about breeding in the wild. However, each generation is estimated to be about 6.6 years. [1] Parallels in altitudinal migration with the equally solitary mockingbird might be taken as indication that the breeding activity peaked around March through April. In captivity, the female generally lays two white eggs in a nest box 1–2.5 m above ground. The incubation lasts from 14 to 17 days, and the young birds fledge after around 14 to 20 days. [3]
The primary reason for the extirpation of the Socorro dove is predation by feral cats, but other pressures may have also contributed. In 1856, sheep were introduced, which resulted in a major alteration to the vegetation of the island, turning most areas below 500 metres (1,600 ft) into open vegetation. This may have caused some decline in their numbers, but did not pose an existential risk to the species. [6] However, in 1957, a military base was established on the island. The evidence found by Jehl and Parkes suggested that feral cats had been introduced at the time that the military base was established, which was ultimately the cause of the species’ extinction. Two expeditions, in 1978 and 1981, failed to find the species, and it was declared extinct in the wild in 1983. [2] [9]
The species avoided complete extinction due to the collection of several doves by an expedition in 1925. The subsequent use of these doves in aviculture resulted in about one hundred doves being available for captive breeding programs, beginning in the late 1980s. [10] The species reproduces no less willingly in captivity than other Zenaida doves, provided its different ecological needs are addressed. As of May 2023, the captive population numbered 156 birds, all in zoos and other facilities in Europe and North America. [3] [11] As of early 2006, it was being prepared to remove the sheep and to rid the island of cats. In the meantime, with the maintenance of the remaining birds, stock for reintroduction is being provided. [3]
In order to protect these birds and eventually reintroduce them into the wild, various reintroduction and conservation efforts have germinated. In 1994, the birds' native island of Socorro was declared a biosphere preserve. [12] [13] In addition, as the number of birds in captivity is only slightly above 100, various associations have begun breeding programs. These include the European Association of Zoos and Aquaria (EAZA) as well as zoos in Frankfurt and Cologne. [14] In 2013, the breeding program was successfully introduced into Mexico by the EAZA in collaboration with various government agencies such as the SEMAR, SEMARNAT, and the Mexican Navy. [15]
Construction of aviaries on Socorro Island began in 2003. Avian Malaria and trichomoniasis were detected during screens of other dove populations on neighboring islands in December 2003 and January 2004. As a result, recommendations for protection of the reintroduction population were put forward. [16] Construction of aviaries was completed in 2005. [16] The same year, plans were outlined to assess the level of soil erosion on Socorro as a result of vegetation loss. [1] In 2006, there was an outbreak of avian influenza in Europe, and therefore 12 doves were sent to Albuquerque Biological Park to create a separate reserve population. [17] In 2008, the Edinburgh and Paignton Zoos sent 12 chicks from their breeding program to the Albuquerque Zoo as part of the collective aggregation effort. [17] The original plan was to reintroduce the birds into Mexico in 2008, but was delayed due to import restrictions and permits, so a stock of viable individuals was kept in the US. [1] In 2010, by using hunting and telemetry, all sheep had been eradicated from the island. [18] The stock aggregated in the United States was finally transferred to Mexico in 2013. [1] As of 2011 [update] , the problem of cats and house-mice has yet to be resolved on Socorro Island. [19] [20]
In addition to efforts to control cats, other animals, and human activity, such as ATV usage, [18] on Socorro Island, efforts are also underway to control locust swarms on the island. [16] Outbreaks of Schistocerca piceifrons have occurred at least twice a year on the island since 1994, and has resulted in damage to native flowers and vegetation. [21]
The burrowing owl, also called the shoco, is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing owls can be found in grasslands, rangelands, agricultural areas, deserts, or any other open, dry area with low vegetation. They nest and roost in burrows, such as those excavated by prairie dogs. Unlike most owls, burrowing owls are often active during the day, although they tend to avoid the midday heat. Like many other kinds of owls, though, burrowing owls do most of their hunting during dusk and dawn, when they can use their night vision and hearing to their advantage. Living in open grasslands as opposed to forests, the burrowing owl has developed longer legs that enable it to sprint, as well as fly, when hunting.
The mourning dove is a member of the dove family, Columbidae. The bird is also known as the American mourning dove, the rain dove, the chueybird, colloquially as the turtle dove, and it was once known as the Carolina pigeon and Carolina turtledove. It is one of the most abundant and widespread North American birds and a popular gamebird, with more than 20 million birds shot annually in the U.S., both for sport and meat. Its ability to sustain its population under such pressure is due to its prolific breeding; in warm areas, one pair may raise up to six broods of two young each in a single year. The wings make an unusual whistling sound upon take-off and landing, a form of sonation. The bird is a strong flier, capable of speeds up to 88 km/h (55 mph).
The Revillagigedo Islands or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem. They lie approximately 458 kilometres (285 mi) from Socorro Island south and southwest of Cabo San Lucas, the southern tip of the Baja California Peninsula, and 698 to 1,092 kilometres west of Manzanillo. Historically linked to the Mexican state of Colima, to which they were granted in 1861 to establish a penal colony, the islands are under Mexican federal property and jurisdiction.
The mourning collared dove or African mourning dove is a dove which is a widespread resident breeding bird in Africa south of the Sahara. Despite its name, it is not related to the North American mourning dove. This species is common or abundant near water. They often mingle peacefully with other doves.
Socorro Island is a volcanic island in the Revillagigedo Islands, a Mexican possession lying 600 kilometres (370 mi) off the country's western coast. The size is 16.5 by 11.5 km, with an area of 132 km2 (51 sq mi). It is the largest of the four islands of the Revillagigedo Archipelago. The last eruption was in 1993.
Andrew Jackson Grayson (1819–1869) was an American ornithologist and artist.
The Socorro mockingbird is an endangered mockingbird endemic to Socorro Island in Mexico's Revillagigedo Islands. The specific epithet commemorates the American ornithologist Andrew Jackson Grayson.
The Guam rail, known locally and in Chamorro as ko'ko', is a small, terrestrial bird endemic to Guam in the Rallidae family. They are one of the island's few remaining endemic bird species. The species became extinct in the wild in the early 1980s when biologists captured the remaining wild population to establish a breeding program. They have since been successfully introduced to the nearby Rota and Cocos islands. In 2019, they became the second bird species to be reclassified by the International Union for the Conservation of Nature from Extinct in the Wild to Critically Endangered.
The tropical parula is a small New World warbler. It breeds from southernmost Texas and northwest Mexico (Sonora) south through Central America to northern Argentina, including Trinidad and Tobago. This widespread and common species is not considered threatened by the IUCN.
The eared dove is a New World dove. It is a resident breeder throughout South America from Colombia to southern Argentina and Chile, and on the offshore islands from the Grenadines southwards. It may be a relatively recent colonist of Tobago and Trinidad. It appears to be partially migratory, its movements driven by food supplies.
Clarion Island, formerly Santa Rosa, is the second largest, westernmost and most remote of Mexico's Revillagigedo Islands. The island is located 385 kilometres (239 mi) west of Socorro Island and just under 700 kilometres (430 mi) from the Mexican mainland.
Townsend's shearwater is a rare seabird of the tropics from the family Procellariidae.
San Benedicto, formerly Isla de los Inocentes, is an uninhabited island, and third largest island of the Revillagigedo Islands, located in the Pacific Ocean.
The Zenaida dove is a member of the bird family Columbidae, which includes doves and pigeons. It is the national bird of Anguilla, where it is locally referred to as "turtle dove".
The white-winged dove is a dove whose native range extends from the Southwestern United States through Mexico, Central America, and the Caribbean. They are large for doves, and can be distinguished from similar doves by the distinctive white edge on their wings. They have a blue eyering, and red eyes. The plumage is brownish-gray to gray. Juveniles are duller in color, and have brown eyes. The call is likened to English phrase "who cooks for you". There are three subspecies. It was first described by George Edwards in 1743, and given its binomial name by Linnaeus in 1756. It was moved into the genus Zenaida in 1838.
Royal Burgers' Zoo is a 45-hectare (110-acre) zoo in Arnhem, Netherlands, and is one of the biggest zoos in the country. Arnhem is a city that lies partially in the Veluwe, a nature park in the east of the Netherlands. The zoo is popular with both Dutch and German people, and receives about 1 million visitors annually. It was founded by Johan Burgers in 1913.
The Galápagos dove is a species of bird in the family Columbidae. It is endemic to the Galápagos Islands. It is fairly common and is found in a wide range of open and semi-open habitats, especially in the arid lowlands of the archipelago.
The Socorro wren is a species of bird in the family Troglodytidae. It is endemic to Socorro Island, Mexico. It was formerly placed in Thryomanes but was moved to Troglodytes considering "manners, song, plumage, etc." and by biogeography and mitochondrial DNA sequence analysis of the MT-NADH dehydrogenase protein 2 gene.
Sideroxylon socorrense is a plant species in the family Sapotaceae. It is endemic to Mexico, native to Socorro Island in the Revillagigedo Islands and to the Pacific coast states of Sinaloa and Nayarit on the Mexican mainland.
Ilex socorroensis is a species of flowering plant in the holly genus (Ilex). It is a tree native to Socorro Island in the Revillagigedo Islands west of Mexico's Pacific coast. It is a small tree, growing up to 8 meters tall.
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