Nesotriccus ridgwayi

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Bibliography

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PASSERIFORMES	TYRANNIDAE

Scientific Name:

Nesotriccus ridgwayi

Species Authority:

Townsend, 1895

Common Name/s:

English

–

Cocos Flycatcher

Assessment Information [top]

Red List Category & Criteria:

Vulnerable D2 ver 3.1

Year Published:

2012

Assessor/s:

BirdLife International

Reviewer/s:

Butchart, S. & Symes, A.

Contributor/s:

Stiles, F.

Justification:
This species is listed as Vulnerable because it has a very small range. Introduced herbivores are degrading habitat within its range, but it appears to tolerate some habitat modification and there is (as yet) no evidence of a decline in range or population.

History:

2008	–	Vulnerable
2006	–	Vulnerable
2004	–	Vulnerable
2000	–	Vulnerable
1996	–	Vulnerable
1994	–	Vulnerable

Geographic Range [top]

Range Description:	Nesotriccus ridgwayi is common throughout Cocos Island, c.500 km off the coast of Costa Rica.
Countries:	Native: Costa Rica
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	The population has been estimated at several tens of thousands of individuals (del Hoyo et al. 2004), but has conservatively been placed in the range band for 10,000-19,999 individuals. This equates to 6,667-13,333 mature individuals, rounded here to 6,000-15,000 mature individuals.
Population Trend:	Stable

Habitat and Ecology [top]

Habitat and Ecology:	It occurs in most habitats from sea-level to the highest hills, including the upper understorey and lower canopy of forests (Stiles and Skutch 1989), Hibiscus scrub, Annona swamp, and wooded ravines. It is regularly observed in second growth (Stiles and Skutch 1989), but degraded habitat may not sustain the species through its life-cycle. The diet consists of insects and, at least seasonally, fruits (Sherry 1985). Breeding probably takes place between January and May.
Systems:	Terrestrial; Freshwater

Habitat and Ecology:

It occurs in most habitats from sea-level to the highest hills, including the upper understorey and lower canopy of forests (Stiles and Skutch 1989), Hibiscus scrub, Annona swamp, and wooded ravines. It is regularly observed in second growth (Stiles and Skutch 1989), but degraded habitat may not sustain the species through its life-cycle. The diet consists of insects and, at least seasonally, fruits (Sherry 1985). Breeding probably takes place between January and May.

Systems:

Terrestrial; Freshwater

Threats [top]

Major Threat(s):	Rats and cats are potential predators, and feral deer, pigs and goats graze suitable habitat. Pigs especially devastate the lower strata and understorey of native forests and inhibit forest regeneration (Sherry 1985, F. G. Stiles in litt. 1999). On many other islands, this combination of feral mammals has caused the extinction of numerous endemic plant and animal species. There is also low-level disturbance from increasing tourism (Sherry 1985).

Major Threat(s):

Rats and cats are potential predators, and feral deer, pigs and goats graze suitable habitat. Pigs especially devastate the lower strata and understorey of native forests and inhibit forest regeneration (Sherry 1985, F. G. Stiles in litt. 1999). On many other islands, this combination of feral mammals has caused the extinction of numerous endemic plant and animal species. There is also low-level disturbance from increasing tourism (Sherry 1985).

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway Cocos has been designated as a national park, but no substantive measures have been taken to reduce populations of introduced mammals (F. G. Stiles in litt. 1999). Conservation Actions Proposed Estimate the population. Study the impact of introduced mammals. Eradicate introduced mammals where feasible.

Conservation Actions:

Conservation Actions Underway
Cocos has been designated as a national park, but no substantive measures have been taken to reduce populations of introduced mammals (F. G. Stiles in litt. 1999).

Conservation Actions Proposed
Estimate the population. Study the impact of introduced mammals. Eradicate introduced mammals where feasible.

Bibliography [top]

	del Hoyo, J.; Elliott, A.; Sargatal, J. 1994. Handbook of the Birds of the World, vol. 2: New World Vultures to Guineafowl. Lynx Edicions, Barcelona, Spain. IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.1). Available at: http://www.iucnredlist.org. (Accessed: 19 June 2012). Sherry, T. W. 1985. Adaptation to a novel environment: food, foraging, and morphology of the Cocos Island Flycatcher. In: Buckley, P.A.; Foster, M.S.; Morton, E.S.; Ridgely, R.S.; Buckley, F.G. (ed.), Neotropical ornithology, pp. 908-920. American Ornithologists' Union, Washington, D.C. Stiles, F. G.; Skutch, A. F. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, NY.

del Hoyo, J.; Elliott, A.; Sargatal, J. 1994. Handbook of the Birds of the World, vol. 2: New World Vultures to Guineafowl. Lynx Edicions, Barcelona, Spain.

IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.1). Available at: http://www.iucnredlist.org. (Accessed: 19 June 2012).

Sherry, T. W. 1985. Adaptation to a novel environment: food, foraging, and morphology of the Cocos Island Flycatcher. In: Buckley, P.A.; Foster, M.S.; Morton, E.S.; Ridgely, R.S.; Buckley, F.G. (ed.), Neotropical ornithology, pp. 908-920. American Ornithologists' Union, Washington, D.C.

Stiles, F. G.; Skutch, A. F. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, NY.

Citation:	BirdLife International 2012. Nesotriccus ridgwayi. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 June 2013.
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