Justification of Red List Category
This species has a very small range which is shrinking as its habitat is cleared for resort development and coconut plantations. However, the range is not yet severely fragmented or restricted to a few locations. In addition, the loss of habitat is suspected to be driving a moderately rapid decline. For these reasons, the species is classified as Near Threatened.
Partners in Flight estimated the population to number fewer than 50,000 individuals (A. Panjabi in litt. 2008), thus it is placed in the band 20,000-49,999 individuals here.
The species is likely to be declining at a moderately rapid rate, owing to the clearance of habitat for tourist development and agriculture.
Melanoptila glabrirostris occurs on the Yucatán peninsula, in Mexico, Belize, and Guatemala. It is a common to fairly common resident on Cozumel Island and from east Quintana Roo, Mexico, to Ambergris Caye, Belize; common to uncommon on Caye Caulker, Lighthouse Reef and Glover's Reef, Belize. Fieldwork on the north coast of the Sian Ka'an Biosphere Reserve has shown the species to be common there (B. Roldán Clarà in litt. 2008). It is only a scarce and perhaps seasonal or accidental (mainly November-May) visitor over much of the Yucatán peninsula, west to Campeche, Mexico, south to Belize and into Petén, north Guatemala (Phillips 1986, Howell and Webb 1995, B. W. Miller in litt. 2007, B. W. Miller in litt. 2008). At least c.40 small breeding colonies have been located in the interior of the Yucatán peninsula, with two composed of at least 100 individuals (including 31 in Yucatán - for example in the Hunucmá area, Izamal and Dzonot Carretero, 6 in Quintana Roo and 2 in Campeche) (B. McKinnon de Montes in litt. 2008, 2011, 2016). There are no records from Honduras since the type-specimen was purportedly collected at Omoa in 1855 or 1856, leading to speculation that the specimen may have been mislabelled (Ridgely and Gwynne 1989). A precipitous decline from c.2003 to 2008 has been reported from Caye Caulker (B. W. Miller in litt. 2008).
It inhabits humid to semi-arid scrubby woodland and forest edge, including seasonally flooded and deciduous forest and secondary growth (P. A. Wood in litt. 2008), but also mangrove and littoral forest on cays (E. McRae in litt. 2008).
Tourism and housing development and conversion to coconut plantations are causing habitat loss and fragmentation in the core of its range on the Quintana Roo coast, Cozumel, and the cays in Belize (Miller and Miller 1991, Stattersfield et al. 1998, E. McRae in litt. 2008, C. J. Sharpe in litt. 2011). It is also potentially threatened by periodic hurricanes, particularly if their frequency and intensity increase; however, impacts from hurricanes have so far not been serious and the species persists in secondary habitats (P. A. Wood in litt. 2008, R. Curry in litt. 2008). Nest predation by Great-tailed Grackle, Quiscalus mexicanus, may be an additional threat to this species (Roldán-Clarà et al. 2013).
Conservation Actions Underway
The Siwa Ban Reserve was designated in 1998 expressly to protect the population on Caye Caulker but it is unclear whether this has provided adequate protection (B. W. Miller in litt. 2000). Belize Caye Development policy grants protection to littoral forest; however, in reality this may not be enforced (E. McRae in litt. 2008) and a considerable area of mangrove has been cleared on Ambergris Caye since the mid-1990s (C. J. Sharpe in litt. 2011). Although it is common in the Sian Ka'an Biosphere Reserve, all of the coastal land is private and house construction is permitted in most areas (B. Roldán Clarà in litt. 2008). In 2009, research was underway to study the genetic and vocal divergence of populations on Cozumel and in the Sian Ka'an Biosphere Reserve. It is on the watch list as part of the State of North America's Birds (North American Bird Conservation Initiative 2016).
Conservation Actions Proposed
Research the species's tolerance to habitat degradation. Adequately protect the important population on Cozumel Island. Enforce the protection afforded to the species by the Siwa Ban Reserve. Investigate where the Yucatan birds go in winter to see if they are a distinct population from those found in the Quintana Roo coastal zone or are from the same population, in which case they definitely need maximum protection (B. MacKinnon de Montes in litt. 2016).
Text account compilers
Capper, D., Mahood, S., O'Brien, A., Sharpe, C J, Taylor, J., Westrip, J.
Wood, P.A., Curry, R., Roldán Clarà, B., McRae, E., LaPergola, J., Clay, R.P., Miller, B., MacKinnon de Montes, B., Sharpe, C J
BirdLife International (2019) Species factsheet: Melanoptila glabrirostris. Downloaded from http://www.birdlife.org on 22/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/10/2019.