VU
San Andres Vireo Vireo caribaeus



Justification

Justification of Red List Category
This species is restricted to an extremely small range on a single island, where it is susceptible to stochastic events and could rapidly become more threatened. However, it has been found to be one of the most common species on the island and to be tolerant of habitat degradation; by now there is no evidence of any significant declines. For these reasons it is classified Vulnerable.

Population justification
In 1998, the species was estimated at 8,200-14,700 individuals (Rosselli 1998); however, this estimate was considered preliminary, as the methodology did not account for detectability differences between habitats nor for the effective population percentage (Gómez-Montes 2011). A population of 8,200-14,700 individuals roughly equates to 5,500-10,000 mature individuals. To account for a potential overestimation of the population size, it is here placed in the band 2,500-9,999 mature individuals. This number may need to be corrected if a more detailed population estimate becomes available.

Trend justification
There is no current evidence for significant declines in the area of suitable habitat available, or of changes in abundance. Thus, the population is suspected to be stable.

Distribution and population

Vireo caribaeus is endemic to San Andrés, Colombia, an island in the west Caribbean, east of Nicaragua. It is apparently now restricted to 17 km2, where it is common.

Ecology

The species reaches highest densities in coconut plantations with scattered trees and scrub, dry lowland woodland and inland mangrove swamps; it occurs at lower densities in mesophytic woodland and brushy pastures (Rosselli 1998, Moreno and Devenish 2003). Within this wide range of habitats, it has a preference for areas of dense understorey vegetation (Rosselli 1998). Breeding territory size ranges from 0.22 to 0.50 ha (Russel et al. 1979, Gómez-Montes and Moreno 2008). Breeding takes place from February to June (Gómez-Montes and Moreno 2008, Gómez-Montes et al. 2010) and seems to be triggered by photoperiod and by the first significant rains after the dry season (Gómez-Montes et al. 2010). Nests are built suspended from the forks of branches, in both mangroves and shrubby bushes (Barlow and Nash 1985). Dry scrub with a ground cover of dead leaves is the preferred nesting habitat (Gómez-Montes and Moreno 2008). Next failure rates of 47% have been recorded, with most failure due to abandonment of eggs (Gómez-Montes and Moreno 2008). The species gleans actively for caterpillars and other arthropods, and feeds fruit to its chicks as well as insects (Rosselli 1998, Gómez-Montes et al. 2010).

Threats

San Andrés is densely populated and developed, with little natural vegetation remaining. The northern 20% of the island is highly urbanised, with tourist developments south of the urban zone. The habitat on most of the remainder of the island has been converted for agriculture and coconut-palm cultivation, but within this area, small and scattered patches of remnant habitat (mostly associated with inland mangroves) and scrub are found. Suitable habitat is highly fragmented. Human population, tourism and agriculture are expanding. Coastal mangroves are being destroyed by waste oil and hot-water outflow, although the extent to which the species is affected is unknown. Exceptional events during the breeding season, such as slash-and-burn and hurricanes, may have an impact on the breeding population (Rosselli 1998).

Conservation actions

Conservation Actions Underway

In 2000, the San Andrés and Providencia Archipelago was declared as the Seaflower Biosphere Reserve. In 2003, an education project was carried out to increase awareness about the species (Moreno and Devenish 2003). There are projects ongoing to investigate the species's biology and breeding ecology (Gómez-Montes and Moreno 2008, Gómez-Montes et al. 2010). In 2006, the Chincherry Bird Reserve was established for this species (C. Gómez-Montes in litt. 2012).

Conservation Actions Proposed

Clarify its distribution, abundance and ecological requirements. Assess the extent and status of native habitat remaining. Identify realistic plantation management practises that will favour this species. Monitor changes in land use and consider active measures to protect remaining habitat. Dry scrubland habitat, which is vital for breeding and currently unprotected, should be conserved (Gómez-Montes and Moreno 2008).

Identification

12.5 cm. Typical vireo with wing-bars and loral stripe. Predominantly olive-green upperparts, including head. Two white wing-bars and pale fringes to flight feathers. Pale yellow stripe from bill base to eye. Whitish underparts, washed pale yellow on flanks and belly. Greyish brown iris. Voice Three different types, unusual among vireos. Repetitive chatter of single-syllable notes, given 2-20 times. Two-syllabled song, se-wi, se-wi, uttered 1-15 times. Variable three-syllabled song. Both sexes have single contact note.

Acknowledgements

Text account compilers
Sharpe, C.J., Gilroy, J., Derhé, M., Benstead, P., Hermes, C.

Contributors
Gómez-Montes, C. & Rosselli, A.


Recommended citation
BirdLife International (2022) Species factsheet: Vireo caribaeus. Downloaded from http://www.birdlife.org on 09/12/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 09/12/2022.