Camarhynchus heliobates

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PASSERIFORMES	EMBERIZIDAE

Scientific Name:

Camarhynchus heliobates

Species Authority:

(Snodgrass & Heller, 1901)

Common Name/s:

English

–

Mangrove Finch

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered B1ab(i,ii,iv,v)+2ab(i,ii,iv,v);C2a(i) ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

Symes, A., Butchart, S., Bird, J.

Contributor/s:

Young, G., Fessl, B., Cruz, F., Vargas, H.

Justification:
This species has an extremely small, severely fragmented range, and potentially as few as two viable subpopulations. Recent surveys suggest that the number of locations and mature individuals are both declining, and consequently it qualifies as Critically Endangered.

History:

2009	–	Critically Endangered
2008	–	Critically Endangered
2004	–	Critically Endangered
2000	–	Critically Endangered
1996	–	Endangered
1994	–	Endangered

Geographic Range [top]

Range Description:	Camarhynchus heliobates is restricted to the Galápagos Islands, Ecuador. Historically, it was known from at least six mangrove patches on east Fernandina and east, south and west Isabela³. Recent surveys have failed to record the species on Fernandina, and it seems likely that it is now extinct as a breeding bird on the island - the last reported sighting may have been in 1971². In 1997 and 1998, surveys on Isabela found breeding populations in only two areas, Playa Tortuga Negra and Caleta Black on the north-west coast of the island, with estimated populations of 37 and 21 pairs respectively^2,3. Subsequent surveys have estimated the population at 36 and 16 pairs in 1999⁴, 24 and 14 pairs in 2007¹⁰, and perhaps the most thorough surveys to date recorded c.40 pairs in each in 2009¹³. Surveys in the fairly extensive mangroves on the south-east coast of Isabela found three to five territories which probably contained breeding birds, but further areas of potentially suitable habitat remain unsurveyed^1,8. In 2008 several other historical sites were surveyed including Punta Espinoza (Fernandina), Bahia Elizabeth, Punta Moreno and Bahia Urbina but the only site at which birds were located was Carthago Bay, where there are thought to be a further 4-5 pairs individuals were seen^11,13.
Countries:	Native: Ecuador
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Perhaps the most accurate surveys to date recorded c.40 territories at Playa Tortuga Negra and Caleta Black, and around five territories at Bahia Carthago. It is thought unlikely that the population varies much from 100 individuals (Fessl et al. 2010), hence a population of 80-120 mature individuals is used here.
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	It inhabits dense mangrove swamps, where it feeds on insects, larvae, spiders and some vegetable matter^1,3,8. Its breeding season coincides with the beginning of heavy rainfalls, normally in December to January, and lasts until the end of the rainy season, around May. Mangroves used by the species in the north-west appear to be structurally different from areas where it is absent suggesting it has subtle habitat preferences and suffers from habitat degradation⁸. It appears to favour mangrove with tall trees, relatively low canopy cover and abundant leaf litter and dead wood⁸. A separation of the mangroves from the sea seems to be crucial as this prevents the washing out of leaf litter etc. (the preferred feeding substrates)⁸.
Systems:	Terrestrial

Habitat and Ecology:

It inhabits dense mangrove swamps, where it feeds on insects, larvae, spiders and some vegetable matter^1,3,8. Its breeding season coincides with the beginning of heavy rainfalls, normally in December to January, and lasts until the end of the rainy season, around May. Mangroves used by the species in the north-west appear to be structurally different from areas where it is absent suggesting it has subtle habitat preferences and suffers from habitat degradation⁸. It appears to favour mangrove with tall trees, relatively low canopy cover and abundant leaf litter and dead wood⁸. A separation of the mangroves from the sea seems to be crucial as this prevents the washing out of leaf litter etc. (the preferred feeding substrates)⁸.

Systems:

Terrestrial

Threats [top]

Major Threat(s):	This species is declining owing to predation and disease as a result of the presence of invasive species. Rattus rattus abundance is high at both breeding sites and is believed to be the major reason for the high nesting failure due to predation (70% in 2007) and low fledgling success¹³. Other possible introduced predators include feral cats (especially important during the post-fledging phase), Smooth-billed Ani Crotophaga ani and fire ants Solenopsis spp., although fire ants seemed to have been successfully exterminated in 1997^2,3,4. The blood-sucking nest parasite Philornis downsi represents a significant threat, as it is present in all nests and infestation is high (mean parasites per nest: 42). The first case of nesting mortality due to Philornis parasitisation was recorded in 2007¹³. Research has shown that the species favours structurally distinct mangroves and hence may be susceptible to human modification of this habitat. Avian pox may also represent a significant threat to the species, which may also be inherently susceptible to the effects of inbreeding¹³.

Major Threat(s):

This species is declining owing to predation and disease as a result of the presence of invasive species. Rattus rattus abundance is high at both breeding sites and is believed to be the major reason for the high nesting failure due to predation (70% in 2007) and low fledgling success¹³. Other possible introduced predators include feral cats (especially important during the post-fledging phase), Smooth-billed Ani Crotophaga ani and fire ants Solenopsis spp., although fire ants seemed to have been successfully exterminated in 1997^2,3,4. The blood-sucking nest parasite Philornis downsi represents a significant threat, as it is present in all nests and infestation is high (mean parasites per nest: 42). The first case of nesting mortality due to Philornis parasitisation was recorded in 2007¹³. Research has shown that the species favours structurally distinct mangroves and hence may be susceptible to human modification of this habitat. Avian pox may also represent a significant threat to the species, which may also be inherently susceptible to the effects of inbreeding¹³.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway The habitat of this species is protected within the Galápagos National Park and, in 1979, the islands were declared a World Heritage Site, although this was classified as threatened in 2007. Predator control is ongoing as is study into the control of Philornis downsi^11,13. A study of breeding biology commenced in 1999⁴ and a follow up study started in 2006. Blood samples are being analysed to investigate the genetic structure of the remaining population and to clarify whether hybridisation is occurring, although preliminary results for the latter are negative⁵. Preliminary results, however, do appear to indicate that the species is highly inbred¹³. A Darwin Initiative funded Mangrove Finch project co-ordinated by Galápagos National Park, Durrell Wildlife Conservation Trust and Charles Darwin Foundation began in 2007⁹ with the aim of clarifying the need and proceedings for a breeding or translocation project. Possible sites for reintroduction have been visited on Isabela and habitat suitability assessments undertaken¹¹. Remote mapping of mangrove has taken place throughout Isabela with the aim of locating suitable sites¹¹, and captive trials have begun using Woodpecker Finches in order to train personnel and develop husbandry techniques that can be transferred to Mangrove Finch in the future¹¹. The current plan is to take ten young birds per year for three years from the main Tortuga Negra colony on the west coast and release them into mangroves on the east coast at Carthago Bay¹². Conservation Actions Proposed Continue to survey dfor further populations. Establish yearly monitoring at Playa Tortuga Negra and Caleta Black². Continue control measures for rats, wasps, anis, cats and fire ants at Playa Tortuga Negra and Caleta Black, and monitor effects on the population². Further study the impact of P. downsi on adults and nestlings, and develop effective control methods

Conservation Actions:

Conservation Actions Underway
The habitat of this species is protected within the Galápagos National Park and, in 1979, the islands were declared a World Heritage Site, although this was classified as threatened in 2007. Predator control is ongoing as is study into the control of Philornis downsi^11,13. A study of breeding biology commenced in 1999⁴ and a follow up study started in 2006. Blood samples are being analysed to investigate the genetic structure of the remaining population and to clarify whether hybridisation is occurring, although preliminary results for the latter are negative⁵. Preliminary results, however, do appear to indicate that the species is highly inbred¹³. A Darwin Initiative funded Mangrove Finch project co-ordinated by Galápagos National Park, Durrell Wildlife Conservation Trust and Charles Darwin Foundation began in 2007⁹ with the aim of clarifying the need and proceedings for a breeding or translocation project. Possible sites for reintroduction have been visited on Isabela and habitat suitability assessments undertaken¹¹. Remote mapping of mangrove has taken place throughout Isabela with the aim of locating suitable sites¹¹, and captive trials have begun using Woodpecker Finches in order to train personnel and develop husbandry techniques that can be transferred to Mangrove Finch in the future¹¹. The current plan is to take ten young birds per year for three years from the main Tortuga Negra colony on the west coast and release them into mangroves on the east coast at Carthago Bay¹².

Conservation Actions Proposed
Continue to survey dfor further populations. Establish yearly monitoring at Playa Tortuga Negra and Caleta Black². Continue control measures for rats, wasps, anis, cats and fire ants at Playa Tortuga Negra and Caleta Black, and monitor effects on the population². Further study the impact of P. downsi on adults and nestlings, and develop effective control methods

Citation:	BirdLife International 2010. Camarhynchus heliobates. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 24 May 2012.
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