Grenada Hook-billed Kite (Chondrohierax uncinatus mirus)
Other names: Grenada Kite, Hook-billed Kite, Mountain Hawk, Snail Kite, Red-collared Kite
Names in Creôle: Merlion, Gree-gree
The Grenada Hook-billed Kite is an endemic subspecies found only in Grenada. It is one of several resident raptors in Grenada, and is commonly confused with the similar-sized Broad-winged Hawk (Buteo platypterus).
- This kite has a very specialized diet of predominantly arboreal snails (Drymaeus, Orthalicus, Bulimulus, Endolichotus) and some terrestrial snails (Pleurodonte). They extract the snail from the shell by holding it against a perch with one foot, and removing the dried membrane covering the aperture with their beak. The shell is then chipped to enlarge the aperture, and the upper mandible is inserted to progressively break the inner whorls of the shell with the tip of the bill, eventually freeing the snail, which is then swallowed whole.
- The Grenada Hook-billed Kite shows much less distinctiveness in both genetic and morphological characters relative to the mainland Hook-billed Kites, but does possess a unique mtDNA suggesting that it may have diverged from the mainland group fairly recently (20,000-190,000 years).
Threats and Conservation Measures
- The main threat is destruction of forested habitat and mature trees which provide habitat for arboreal snails and nesting sites for kites. Development for tourism and increasing population in the country threaten remaining forest in Grenada. There is some forest habit destruction with construction of individual homes. In the future habitat modification will likely occur with increased tourism. The only protected areas the kites occur in are where habitat has been protected for the Grenada Dove: Mt. Hartman and Perseverance.
- Grenada Hook-billed Kite is legally protected from hunting, but may suffer from human persecution and young boys using sling shots because the species is often confused with the more common Broad-winged Hawk which may take young chickens.
- The Peregrine Fund and Ministry of Forestry have been studying the species and there was monitoring of its population from 2000-2006. There has been no monitoring of the population or breeding attempts since December 2006. An education program by the Ministry of Forestry has worked to raise awareness about the endangered status of the kite, to teach people to identify it so that it is not confused with the Broad-winged Hawk, and to raise pride in this endemic subspecies. A poster, brochure, and conservation buttons were produced and distributed.
- Small population size makes this endemic kite vulnerable to disease and any climatic conditions that may negatively impact the forested habitat in Grenada, such as possible changes in forest cover from global warming and devastation of forests from hurricanes and storms (which are predicted to increase with global warming). Recent hurricanes appeared to impact the population and breeding attempts in 2005 post-hurricanes Ivan and Emily. Prior to the two hurricanes a high of 10 breeding attempts and 39 individuals were recorded. Many mature trees were stripped of leaves and branches, and some were uprooted. There was only one breeding attempt in 2005 with only 16 individuals recorded. The impact on the population and the kite's ability to breed, may have been due to a lack of food and available nesting sites post-hurricane, but by 2006 six breeding attempts were documented.
Where to Find More Information?
Blockstein, D. E. 1988. Two endangered birds of Grenada, West Indies: Grenada Dove and Grenada Hook-billed Kite. Caribb. J. Sci. 24: 127–136.
Blockstein, D. E. 1991. Population decline of the endangered endemic birds of Grenada, West Indies. Bird Cons. Int. 1: 83–91.
del Hoyo, J., A. Elliot, and J. Sargatal. 1994. Handbook of the birds of the world. Volume 2: New World vultures to guineafowl. Lynx Edicions, Barcelona, Spain.
Ferguson-Lees, J. and D. A. Christie. 2001. Raptors of the World. Christopher Helms, London, UK.
Global Raptor Information Network. 2008. Species account: Hook-billed Kite Chondrohierax uncinatus. Downloaded from http://www.globalraptors.org on 27 Feb. 2008.
Johnson, J., R. Thorstrom, and D. Mindell. 2007. Systematics and Conservation of the Hook-billed Kite including the island taxa from Cuba and Grenada. Animal Cons. 10: 1–11.
Lack, D. and A. Lack. 1973. Birds of Grenada. Ibis 115: 53–59.
Smith, T. B. and S. A. Temple. 1982. Grenada Hook-billed Kites: recent status and life history notes. Condor 84: 131.
Thorstrom, R., E. Massiah, and C. Hall. 2001. Nesting biology, distribution, and population estimate of the Grenada Hook-billed Kite Chondrohierax uncinatus mirus. Caribb. J. Sci. 37: 278–281.
Thorstrom, R., and D. McQueen. In press. Breeding and status of the Grenada Hook-billed Kite (Chondrohierax uncinatus mirus). Ornitologia Neotropical.
Wheeler, B. K., and W. S. Clark. A photographic guide to North American Raptors. Academic Press, London, U.K.
Grenada Hook-billed Kite Bird of the Month contributed by Russell Thorstrom
Photographs by Russell Thorstrom
Guidelines for writing up a Bird of the Month - please send in your contributions!
Bird of the Month - April 2008 - Trinidad Piping Guan or Pawi
Bird of the Month - December 2007 - Hispaniolan Parrot
Bird of the Month - September 2007 - Piping Plover
Bird of the Month - April 2007 - Montserrat Oriole
Bird of the Month - March 2007 - Grenada Dove
Bird of the Month - January 2007 - Bicknell's Thrush
Bird of the Month - December 2006 - Rose-throated Parrot
Bird of the Month - November 2006 - Purple-Throated Carib
Bird of the Month - October 2006 - Palmchat
Bird of the Month - September 2006 - Elfin-woods Warbler
Bird of the Month - August 2006 - Red-billed Streamertail
Bird of the Month - July 2006 - Cahow or Bermuda Petrel
Bird of the Month - June 2006 - West Indian Whistling-Duck