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Overview

Distribution

Range Description

Mimus graysoni is endemic to Socorro in the Revillagigedo Islands, Mexico. It was the most abundant and widespread landbird in 1925, and was still abundant in 1958. By 1978, it had declined dramatically and was feared on the verge of extinction. Subsequent surveys have estimated the population at 50-200 pairs in 1988-1990 (Castellanos and Rodrguez-Estrella 1993, Wehtje et al. 1993, Rodrguez-Estrella et al. 1996) and c.350 individuals in 1993-1994, with the highest densities in the sheep-free dwarf forests of Cerro Evermann (Martnez-Gmez and Curry 1996). Of 170 birds ringed in 1994, 56% were subadults (Martnez-Gmez and Curry 1996), suggesting that productivity is high and the population would be capable of increasing if habitat quality improves across the island (J. E. Martnez-Gmez in litt. 2007).

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Source: IUCN

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Range

Socorro I. (Revillagigedo Islands off w Mexico)..
  • Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2014. The eBird/Clements checklist of birds of the world: Version 6.9. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/

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Historic Range:


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Physical Description

Type Information

Type for Mimodes graysoni
Catalog Number: USNM 39987
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Birds
Sex/Stage: Male; Adult
Preparation: Skin: Whole
Collector(s): A. Grayson
Year Collected: 1865
Locality: Socorro Island, Isla Socorro, Revillagigedo Islands, North Pacific Ocean
  • Type: Lawrence. "February-March" 1871. Ann. Lyc. Nat. Hist. New York. 10 (1-3): 1.
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© Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Birds

Source: National Museum of Natural History Collections

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Type for Mimodes graysoni
Catalog Number: USNM 39987
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Birds
Sex/Stage: Male; Adult
Preparation: Skin: Whole
Collector(s): A. Grayson
Year Collected: 1865
Locality: Socorro Island, Isla Socorro, Revillagigedo Islands, North Pacific Ocean
  • Type: Lawrence. "February-March" 1871. Ann. Lyc. Nat. Hist. New York. 10 (1-3): 1.
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© Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Birds

Source: National Museum of Natural History Collections

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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
It occurs principally in moist dwarf forest and ravines with a mixture of shrubs and trees at elevations above 600 m (Martnez-Gmez and Curry 1996). Vegetation in these areas is dominated by the trees Ilex socorrensis, Guettarda insularis and Oreopanax xalapensis and the understorey species Triumfetta socorrensis and Eupatorium pacificum (Martnez-Gmez and Curry 1996, Martnez-Gmez et al. 2001). It is very rare at low and mid-elevations (0-500 m), and absent from areas of Croton masonii scrub near sea-level and sheep-damaged habitat in the south-east half of the island (Martnez-Gmez and Curry 1996, Martnez-Gmez et al. 2001), but is common within fig Ficus cotinifolia patches in the north-west of the island (J. E. Martnez-Gmez in litt. 2007). Fig groves may act as regeneration nuclei for the species, supporting birds when a suitable understorey is present (J. E. Martnez-Gmez in litt. 2007). Nesting may occur from November-July with a peak in March-April (Martnez-Gmez and Curry 1995). Three eggs are laid and the incubation period is no more than 15 days (Martnez-Gmez and Curry 1995). Food includes crab remains, small invertebrates and fruit, particularly those of Ilex socorrensis and Bumelia socorrensis (Castellanos and Rodrguez-Estrella 1993, Martnez-Gmez et al. 2001).


Systems
  • Terrestrial
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Source: IUCN

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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
CR
Critically Endangered

Red List Criteria
B1ab(ii,iii)

Version
3.1

Year Assessed
2013

Assessor/s
BirdLife International

Reviewer/s
Butchart, S.

Contributor/s
Keitt, B., Martnez-Gmez, J. & Tershy, B.

Justification
Intensive sheep-grazing and a persistent locust swarm are reducing and degrading habitat for this species. Combined with cat predation, which effectively removes mockingbirds from areas with little or no understorey, declines in its very small population and extremely small range are considered likely. This combination of factors qualifies the species as Critically Endangered.


History
  • 2012
    Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Endangered (EN)
  • Endangered (EN)
  • Threatened (T)