Data Zone
Justification of Red List category
This species is considered Critically Endangered because it has an extremely small population, which is inferred to be undergoing a continuing decline. The combination of major population reduction events due to periodic severe hurricanes, and the impacts of impacts of invasive species plus habitat loss preventing population recovery between hurricanes leaves the species at very high risk of extinction.
Population justification
The global population is estimated at 136-182 mature individuals (Rivera-Milán et al. 2015).
The population structure has not been assessed. While the species's two strongholds around Mt Hartman National Park and on the Perseverance and adjacent Woodford estates are separated by 9 km of highly converted habitat (Rusk 2017), there are occasional records of single individuals dispersing outside of these areas (Rivera-Milán et al. 2015, Rusk 2017). It is therefore tentatively assumed that the individuals in both areas are able to get in contact, forming just one subpopulation, though this requires confirmation.
Trend justification
The population was estimated at 98-124 mature individuals in 1998, climbing to 182 mature individuals by 2003-2004. Although these figures suggest that the population may have increased between 1998 and 2004, the latter estimate included c. 30 mature individuals discovered in 2003, and increases may reflect an improvement in sampling methods. However, the population declined after category IV hurricane Ivan caused severe damage in 2004, and the three years after the hurricane the population was still 25% below the numbers from 2004, with a maximum of 136 mature individuals (Rusk 2017). In 2013, the population was estimated at 136-182 mature individuals (Rivera-Milán et al. 2015).
While the population appears to have stabilised or even increased over the past three generations (14.1 years; Bird et al. 2020), it shows fluctuations in relation to hurricanes (Baptista et al. 2020). The intensity, and probably the frequency, of hurricanes in the Atlantic are projected to increase with climate change (see e.g., Knutson et al. 2010; Walsh et al. 2016). Therefore, it is inferred that the population is continuing to decline, as the population is deemed unable to recover between events of major reductions caused by hurricanes, in conjunction with other threats.
The species is endemic to Grenada in the Lesser Antilles. Historically, it was more widespread in coastal and possibly offshore islands, but may always have been rare (Devas 1943). The species is now confined to two areas in the southwest of the island in and around Mt Hartman National Park, and in the west in the Perseverance, Woodford and Beausejour area (Rusk 2017). These two strongholds are separated by 9 km of highly developed and urbanised areas (Rusk 2017). Occasionally, there are reports of single individuals outside of these areas, including on the east of the island (Rivera-Milán et al. 2015, Rusk 2017).
The species inhabits undisturbed areas of dry, coastal scrub-woodland up to 150 m elevation. In the south-west, its habitat comprises a closed canopy of leguminous, often thorny trees and shrubs c.3-6 m high, a sparse understorey of shrubs and saplings, sparse to absent ground-cover and much exposed soil (Blockstein 1991). The flowering tree Haematoxylum campechianum is dominant in these areas (Rusk 1992, Baptista et al. 2020). On the west coast, its habitat also includes some mixed deciduous and evergreen vegetation. It may have been always confined to xeric, coastal areas where climax vegetation was deciduous, seasonal forest and thorn woodland, but frequent natural disturbances (particularly hurricanes) kept the vegetation in a sub-climax condition (Rusk et al. 2008). This temporary occupation of ephemeral patches and recolonisation of developing patches may be the normal life history pattern.
Breeding is limited to the rainy season in the south-west, but is more extended on the less xeric west coast (Rusk 1998).
Hurricanes pose a pertinent threat to the remaining population (Rusk 2017). Following category IV hurricane Ivan in 2004, calling frequency by males during the breeding season appeared to have fallen significantly, possibly as a result of stress owing to limited resources (Rusk 2005). The hurricane damaged habitat structure and allowed the invasion of alien vines into suitable dove habitat. As hurricanes are projected to increase in intensity and probably also frequency in the Caribbean with climate change (see e.g., Knutson et al. 2010, Walsh et al. 2016), the risk posed by hurricanes is likely to increase in the near future. Climate change is adding a further threat to the species, as an increase in drought events is leading to a higher frequency of fires and a limited availability of fresh water during the dry season (Rusk 2011, Baptista et al. 2020).
Habitat loss due to clearing for small plantations and charcoal production has been replaced in recent years with chronic and continuing habitat loss for residential housing, roads, commercial and other development. Habitat on private land is vulnerable to development and high land prices mean that it is not practical for the government to purchase these areas to ensure their protection (Anon. 2012). Forest clearing was substantially reduced at the Mt. Hartman Estate by the late 1990s due to the establishment of the Mt. Hartman National Park and Dove Sanctuary and the cessation of farming on the remainder of the estate (Rusk 1998). Nevertheless, in 1995, 50% of Perseverance was clear-cut for a planned quarry, with half the site now a sanitary land-fill (Rusk and Temple 1995). A lease was granted for a new quarry at this site in 2008, but that was temporarily halted in 2009 (Rusk 2008, 2010). Increases in squatters and cattle in the 1990s resulted in more disturbance at Perseverance, though currently habitat degradation is due to garbage and toxic fumes invading the site from the garbage dump across the road as well as spillover from the adjacent hurricane debris site (Rusk 2008, 2010). A resort development proposed in 2015 at Mt. Hartman National Park poses a significant threat, and would have a serious impact on the adjacent protected habitat, unless mitigation measures including a predator exclusion fence are put in place to protect the species (B. L. Rusk in litt. 2016). This development would displace all doves outside the national park. Resort planning was halted in 2016, but has since resumed (B. L. Rusk in litt. 2016, Baptista et al. 2020). Nevertheless, it is planned to minimise the impact on the species and the boundaries of the national park were expanded to include all areas where individuals are present (Baptista et al. 2020).
Population declines are likely to be compounded further by high numbers of introduced mongooses (Herpestes auropunctatus), cats (Felis catus), rats (Rattus spp.) and opposums (Didelphis marsupialis) predating eggs and fledglings, of which mongoose were found to be the most abundant (Rusk 2015), but rats the most widespread (Twyman and Hyslette unpubl. data). It is possible that mongooses and cats are able to climb diagonal branches and trunks to reach the birds. By 2012, mongoose numbers had reached levels whereby they were found to occur daily across much of Grenada Dove habitat (Bolton et al. 2015).
Conservation Actions Underway
Grenada Dove is the national bird of Grenada, has been a focus of environmental education in schools and ecotourism, and features on stamps. In 1996, parts of the Mt. Hartman and Perseverance estates were declared a national park and a protected area, respectively. A four-year GEF/WB funded Dry Forest Biodiversity Conservation Project based on stakeholder input was implemented from 2001-2006. A recovery plan was drafted in 1998; in 2008, it was revised and updated for a further 10 years (Rusk et al. 2008). In 2011, critical habitat on crown lands at the Beausejour Estate (c.100 acres) received approval by the Government of Grenada cabinet for its protection and addition to the Perseverance Protected Area (Rusk 2011).
In 2010, dove habitats on private lands at Beausejour, Grenville Vale and Woodford were recommended for protection in the Conservation and Management Plan for Perseverance Protected/Beausejour Area. All areas currently occupied by doves are now IBAs and are included in Grenada's System Plan for Parks and Protected Areas. A legislative review to address private lands slated for protection has taken place in 2013. The Grenada Dove Conservation Programme (GDCP), with the Forestry and National Parks Department (FNDP), is collaborating with Birds Caribbean with the aim of developing eco-tourism activities in two of the key areas for the species (Mt. Hartman and Beausejour) (Anon. 2013). This collaboration has resulted in extensive interpretation at the Mt. Hartman Visitor Center, a school outreach programme and increased student site visitation.
Predator control measures at dove sites were initiated in 2014, with over 1,000 mongoose trapped and removed at Mt. Hartman in an 18 month period. The Grenada Dove Conservation Programme and Forestry and National Parks Department collaborated with the University of Chester (2014-2015) to study tropical dry forest changes (including dove habitat) using historical and current data, and to look at possible future changes using climate change modelling scenarios. The species is legally protected from hunting and egg-collecting, but these threats are insignificant.
Conservation Actions Proposed
Carry out regular surveys to quantify the population size. Undertake research into the species's ecology, including home range size, habitat preferences and sex ratio (Bolton et al. 2015). Establish a long-term monitoring programme to determine population trends. Monitor rates of habitat loss and degradation.
Continue to protect remaining habitat. Formally protect important habitat that falls within private lands (Rusk 2011). Ensure that the Mt. Hartman National Park and Perseverance Reserve are effectively managed. Prevent developments within or near the Mt. Hartman National Park. Address other limiting factors and implement species management activities, including supplemental food and water. Provide alternatives to standing water sources such as 'leaky' hose water stations to reduce the risk of disease (Bolton et al. 2015). Eliminate, or at least mitigate, further habitat loss. Restore suitable habitat.
Continue and expand the control programmes to reduce mongoose, rat and cat presence in dove habitat and monitor and manage numbers of other introduced predators (Bolton et al. 2015). Erect a predator exclusion fence around Mt. Hartman National Park.
Consider establishing a a captive breeding programme, with the aim to reintroduce new subpopulations.
Develop incentives and regulations for the protection of suitable habitat on private residential lots in the south-west adjacent to Mt. Hartman, and Beausejour and Woodford on the west coast (B. L. Rusk unpubl. data).
31 cm. Medium-sized, plump bicoloured dove. Brown upperparts, with white forehead and white breast feathers that extend around shoulder. White underparts with pinkish-brown breast, plain dark wings, tail tipped white, and pale eye. Shows cinnamon underwing in flight. Pinkish red legs, feet and bare skin around the eyes. Similar spp. Eared Dove Zenaida auriculata is smaller, more uniform brown with dark eye and auricular mark, black spots on scapulars and no white in tail. Voice Mournful descending hoooo, repeated at seven to eight-second intervals.
Text account compilers
Everest, J., Hermes, C.
Contributors
Ashpole, J, Benstead, P., Bird, J., Blockstein, D., Butchart, S., Calvert, R., Capper, D., Collar, N., Ellard, J., Khwaja, N., Rusk, B., Sharpe, C.J., Symes, A., Wege, D. & Wheatley, H.
Recommended citation
BirdLife International (2024) Species factsheet: Grenada Dove Leptotila wellsi. Downloaded from
https://datazone.birdlife.org/species/factsheet/grenada-dove-leptotila-wellsi on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/11/2024.