Zenaida graysoni

Taxonomy

Assessment Information

Geographic Range

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	COLUMBIFORMES	COLUMBIDAE

Scientific Name:

Zenaida graysoni

Species Authority:

Lawrence, 1871

Common Name/s:

English

–

Socorro Dove

Assessment Information [top]

Red List Category & Criteria:

Extinct in the Wild ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

Symes, A., Butchart, S.

Contributor/s:

Stadler, S., Martínez-Gómez, J., Tershy, B., Horblit, H.

Justification:
The last record of an individual of this species in its natural habitat was in 1972. It is therefore classified as Extinct in the Wild. However, there are c.100 birds in captivity and reintroduction of the species is planned.

History:

2008	–	Extinct in the Wild
2004	–	Extinct in the Wild
2000	–	Extinct in the Wild
1996	–	Extinct in the Wild
1994	–	Extinct in the Wild

Geographic Range [top]

Range Description:	Zenaida graysoni has been extirpated from Socorro in the Revillagigedo Islands, Mexico. It was formerly common and observations in 1957 and 1958 gave no indication that it was declining. The last sighting in the wild was in 1972¹, and all suitable habitat on the island has been surveyed subsequently without recording the dove². Several individuals were taken during an expedition to the islands in 1925 and subsequently bred in the USA, with some sent to Europe⁴. Fortunately, aviculture has prevented the extinction of the species, with captive populations are held in USA and 12 European countries⁹. The European Breeding Programme for this endangered species has monitored the captive population for more than 30 years⁹. The captive population was thought to total several hundred birds, but hybridisation with Mourning Doves Z. macroura became a major problem in the USA in the 1990s⁴, and it now appears that many are hybrids².
Range Map:	Click here to open the map viewer and explore range.

Range Description:

Zenaida graysoni has been extirpated from Socorro in the Revillagigedo Islands, Mexico. It was formerly common and observations in 1957 and 1958 gave no indication that it was declining. The last sighting in the wild was in 1972¹, and all suitable habitat on the island has been surveyed subsequently without recording the dove². Several individuals were taken during an expedition to the islands in 1925 and subsequently bred in the USA, with some sent to Europe⁴. Fortunately, aviculture has prevented the extinction of the species, with captive populations are held in USA and 12 European countries⁹. The European Breeding Programme for this endangered species has monitored the captive population for more than 30 years⁹. The captive population was thought to total several hundred birds, but hybridisation with Mourning Doves Z. macroura became a major problem in the USA in the 1990s⁴, and it now appears that many are hybrids².

Range Map:

Click here to open the map viewer and explore range.

Habitat and Ecology [top]

Habitat and Ecology:	It was apparently commonest in forested areas above 500 m, dominated by Bumelia, Prunus serotina, Guettarda, Ilex, Psidium and Ficus. It was a highly terrestrial frugivore, and probably depended on an intact understorey of ferns and euphorbias.
Systems:	Terrestrial

Threats [top]

Major Threat(s):	The decline and extinction in the wild of Z. graysoni has been attributed chiefly to predation by cats. However, it was thought that cats became feral on Socorro in the 1950s, but this date has now been revised to the early 1970s². This suggests that other factors, such as human predation⁴ and high levels of understorey grazing by sheep, may have been significant. Outbreaks of a permanent locust Schistocerca piceifrons swarm have occurred twice a year since 1994, resulting in damage to the leaves, flowers and fruit of indigenous forests, with at least 30 ha lost to defoliation so far, thus reducing the extent of prime habitat for the species⁹. Locust outbreaks may be favoured by the habitat degradation caused by introduced species¹³.

Major Threat(s):

The decline and extinction in the wild of Z. graysoni has been attributed chiefly to predation by cats. However, it was thought that cats became feral on Socorro in the 1950s, but this date has now been revised to the early 1970s². This suggests that other factors, such as human predation⁴ and high levels of understorey grazing by sheep, may have been significant. Outbreaks of a permanent locust Schistocerca piceifrons swarm have occurred twice a year since 1994, resulting in damage to the leaves, flowers and fruit of indigenous forests, with at least 30 ha lost to defoliation so far, thus reducing the extent of prime habitat for the species⁹. Locust outbreaks may be favoured by the habitat degradation caused by introduced species¹³.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway The Revillagigedo Islands were declared a biosphere reserve in 1994^4,10. In 1995, the European Association of Zoos and Aquaria recognised a breeding programme for the species, as initiated by Cologne and Frankfurt Zoos (Germany) and the private interest group Wild Pigeons and Doves, as an official European Endangered Species Programme (EEP)⁴. Modern studbook software has been employed to assist with the genetic and demographic management of the captive population. Individuals have been distributed to zoos and bird parks in Belgium, The Netherlands, UK, Poland, Austria, Luxembourg, France, Spain and Germany, at least¹¹. Of 563 individuals listed in the studbook by December 2006, 104 were known to be alive. In 2006, following an extensive survey of the origin of the founding individuals of the EEP population, a major software based population genetic analysis was conducted and recommendations for new pairs were given by the EEP coordinator¹¹. A special breeding unit for the species has been opened at Marlow Bird Park, Germany⁴. A proposal is currently being developed to reintroduce the species^1,4, along with a restoration programme for Socorro^4,7. DNA fingerprinting has revealed extensive hybridisation with Z. macroura in the USA, however it also showed a high degree of relatedness between the European population and pure individuals kept in California⁴. As a result, the European population will be used for reintroduction efforts. The construction of breeding aviaries on Socorro began in August 2003⁴ and was completed by 2005⁵. The island's columbid populations (Z. macroura and Socorro Gound-dove Columbina passerina socorroensis)⁵ were screened in December 2003 and January 2004 to assess the presence of pathogens that might affect the reintroduction programme^4,5,6. Avian malaria and Trichomoniasis were detected in both species, and as a result recommendations were put forward^5,6. In 2005, plans were outlined to control the locust outbreaks, restore native vegetation and assess the problem of erosion⁸. The arrival on Socorro of the first captive birds from Germany was planned for June 2005⁶, with the establishment of a captive flock by June 2006⁵. However, there have been problems with import restrictions and permits⁹. In the face of these restrictions a small insurance population will be established in the USA in 2008^9,12. Some control of feral cats has been undertaken on Socorro³, and there are plans to eradicate cats in 2009, at the earliest¹⁴. Reports that rats have recently colonised Socorro have proved to be unfounded². The sheep population has been reduced to c.300 by the Mexican Navy⁹. Sheep eradication is planned for 2008-2009¹⁴. Conservation Actions Proposed Import captive birds from Germany and establish a captive flock on Socorro^5,6,9. Complete the eradication of cats and sheep on Socorro^8,9. Continue to restore native vegetation on Socorro⁸. Reintroduce the species following satisfactory progress in the mammal eradication^8,9 and habitat restoration programmes^4,7,8. Put measures in place to control, but not eliminate, the locust swarm^8,13.

Conservation Actions:

Conservation Actions Underway
The Revillagigedo Islands were declared a biosphere reserve in 1994^4,10. In 1995, the European Association of Zoos and Aquaria recognised a breeding programme for the species, as initiated by Cologne and Frankfurt Zoos (Germany) and the private interest group Wild Pigeons and Doves, as an official European Endangered Species Programme (EEP)⁴. Modern studbook software has been employed to assist with the genetic and demographic management of the captive population. Individuals have been distributed to zoos and bird parks in Belgium, The Netherlands, UK, Poland, Austria, Luxembourg, France, Spain and Germany, at least¹¹. Of 563 individuals listed in the studbook by December 2006, 104 were known to be alive. In 2006, following an extensive survey of the origin of the founding individuals of the EEP population, a major software based population genetic analysis was conducted and recommendations for new pairs were given by the EEP coordinator¹¹. A special breeding unit for the species has been opened at Marlow Bird Park, Germany⁴. A proposal is currently being developed to reintroduce the species^1,4, along with a restoration programme for Socorro^4,7. DNA fingerprinting has revealed extensive hybridisation with Z. macroura in the USA, however it also showed a high degree of relatedness between the European population and pure individuals kept in California⁴. As a result, the European population will be used for reintroduction efforts. The construction of breeding aviaries on Socorro began in August 2003⁴ and was completed by 2005⁵. The island's columbid populations (Z. macroura and Socorro Gound-dove Columbina passerina socorroensis)⁵ were screened in December 2003 and January 2004 to assess the presence of pathogens that might affect the reintroduction programme^4,5,6. Avian malaria and Trichomoniasis were detected in both species, and as a result recommendations were put forward^5,6. In 2005, plans were outlined to control the locust outbreaks, restore native vegetation and assess the problem of erosion⁸. The arrival on Socorro of the first captive birds from Germany was planned for June 2005⁶, with the establishment of a captive flock by June 2006⁵. However, there have been problems with import restrictions and permits⁹. In the face of these restrictions a small insurance population will be established in the USA in 2008^9,12. Some control of feral cats has been undertaken on Socorro³, and there are plans to eradicate cats in 2009, at the earliest¹⁴. Reports that rats have recently colonised Socorro have proved to be unfounded². The sheep population has been reduced to c.300 by the Mexican Navy⁹. Sheep eradication is planned for 2008-2009¹⁴.

Conservation Actions Proposed
Import captive birds from Germany and establish a captive flock on Socorro^5,6,9. Complete the eradication of cats and sheep on Socorro^8,9. Continue to restore native vegetation on Socorro⁸. Reintroduce the species following satisfactory progress in the mammal eradication^8,9 and habitat restoration programmes^4,7,8. Put measures in place to control, but not eliminate, the locust swarm^8,13.

Citation:	BirdLife International 2010. Zenaida graysoni. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 26 May 2012.
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