Navassa Island National Wildlife Refuge: Caribbean Island of Birds

Summary: Navassa Island, a Caribbean island of birds, hosts Navassa Island National Wildlife Refuge as the United States 517th National Wildlife Refuge.

red-footed boobies (Sula sula), Lulu Bay, southwest coast of Navassa Island: US Geological Survey, Public Domain, via USGS Coastal and Marine Geology Program/St. Petersburg Coastal and Marine Science Center

Navassa Island, a tiny, pear-shaped island in the Jamaica Channel between the islands of Hispaniola and Jamaica, is a species-rich haven which includes seabirds and other birds among residents and visitors.

On April 22, 1999, Navassa became the United States’ 517th National Wildlife Refuge. Administered by the US Fish and Wildlife Service (USFWS), the refuge became the eighth unit of the Caribbean Islands National Wildlife Refuge Complex. Unique characteristics and resources distinguish each of the complex’s nine units, of which five are located in the Commonwealth of Puerto Rico (Cabo Rojo, Culebra, Desecheo, Laguna Cartagena, Vieques) and three are found in the U.S. Virgin Islands (Buck Island, Green Cay, Sandy Point).

Five inventory expeditions conducted by the USFWS between July 1998 and October 2006 have increased the species list to 58 with the addition of 18 new bird records. In addition to ideal nesting sites on sparsely vegetated limestone cliffs, resident land birds, Neotropical migrants and nesting seabirds claim scattered savanna grasslands and four dominant tree species in Navassa’s subtropical dry forest -- pigeon plum (Coccoloba diversifolia), poisonwood (Metopium brownei), poplarleaf fig (Ficus populnea), yellow mastic (Sideroxylon foetidissimum) -- as habitats.

Red-footed boobies (Sula sula) and magnificent frigate birds (Fregata magnificens) nest and roost in populations estimated in the hundreds and thousands as year-round seabird residents of the minuscule, (5.2 square kilometer) island. Three other seabirds that commonly nest on Navassa’s desirable cliffs -- bridled tern (Onychoprion anaethetus), brown booby (Sula leucogaster), brown noddies (Anous stolidus) -- may join red-footed boobies and magnificent frigate birds in year-round residency.

Uncommon appearances by the ashy-faced owl (Tyto glaucops) and the white-necked crow (Corvus leucognaphalus) either represent migratory visits or permanent residence. Both birds, of which the white-necked crow is listed as a vulnerable endangered species, are native to the nearby island of Hispaniola.

During the fourth USFWS expedition, taking place from Dec. 5 to 10, 2001, researchers learned, by communicating with transient Haitian fisherman, in broken French and sign language and by referencing an illustrated bird guide, that the itinerant campers capture and eat brown boobies, red-footed boobies, and magnificent frigate birds.

Year-round populations of black rats (Rattus rattus), as well as feral dogs (Canis domesticus) and goats (Capra hircus), join human transients in posing threats to Navassa’s avian residents and visitors. As the most common island-introduced species, mammals negatively impact migratory and native bird populations. Especially seabirds, which depend upon islands for breeding sites, undergo serious population threats from feral mammals. The uncontrolled settings of such uninhabited islands as Navassa offer ideal sites for extreme threats to bird populations by feral mammals.

As acknowledged by researchers with USFWS’s five expeditions, the future of Navassa Island’s endemic, migratory, and native species depends upon effective management of the island as a national wildlife refuge. Management priorities include conservation and restoration of the subtropical dry forest habitat, elimination of feral mammals, and impact assessment of such unauthorized visitors as transient fishermen.

With effective management, Navassa Island will continue to shelter healthy populations of native species, including seabirds. As a safe haven, Navassa Island National Wildlife Refuge will live up to the nickname of “mini-Galápagos” bestowed upon the species-rich island by Roger McManus, president of the Center for Marine Conservation (CMC), which co-sponsored with the US Department of the Interior and the Henry Luce Foundation two inventory expeditions identifying 800 terrestrial species in 1998 and 1999.

sea cliffs along Navassa's east coast: Navassa's limestone cliffs are forbidding to humans but welcoming as nesting sites for birds: US Geological Survey, Public Domain, via USGS Coastal and Marine Geology Program/St. Petersburg Coastal and Marine Science Center

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Red-footed boobies (Sula sula), Lulu Bay, southwest coast of Navassa Island: US Geological Survey, Public Domain, via USGS Coastal and Marine Geology Program/St. Petersburg Coastal and Marine Science Center @ http://coastal.er.usgs.gov/navassa/biology/fauna3.html

Navassa's east coast: US Geological Survey, Public Domain, via USGS Coastal and Marine Geology Program/St. Petersburg Coastal and Marine Science Center @ http://coastal.er.usgs.gov/navassa/geology/terraces10.html

For further information:

Earsom, Stephen D., Claudia Lombard, Joseph Schwagerl, James P. Oland, and Leopoldo Miranda-Castro. “Avifauna and Human Disturbance Observations on Navassa Island.” Caribbean Journal of Science, vol. 44, no. 2 (July 2008): 246-251.
Available @ http://caribjsci.org/July08/44_246-251.pdf

Marriner, Derdriu. "Navassa Island Lighthouse: Crumbling Landmark Deactivated Since 1966." Earth and Space News. Wednesday, Oct. 14, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/10/navassa-island-lighthouse-crumbling.html

Marriner, Derdriu. "Navassa Island Unofficial Flag: Designed for 2001 USS Arizona Tribute." Earth and Space News. Sunday, Oct. 18, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/10/navassa-island-unofficial-flag-designed.html

Marriner, Derdriu. "Navassa Island: US Fish and Wildlife Service Uninhabited Caribbean Island." Earth and Space News. Saturday, Oct. 10, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/10/navassa-island-us-fish-and-wildlife.html

Showstack, Randy. “In Brief.” Eos, vol. 79, no. 34 (August 25, 1998): 406.
Available @ DOI: 10.1029/98EO00312.