Magens Bay

Year of compilation: 2007

Site description
Magens Bay is located on the north central coast of St. Thomas, opens northwesterly into the Atlantic, and includes an extensive sandy beach, coastal mangrove wetlands, and deciduous dry and moist forests. Within the site is Magen’s Bay Preserve, a 129 hectare preserve co-owned and managed by The Nature Conservancy, the Magens Bay Authority and the V.I. Territorial Government. The Preserve, established in 2002 by The Nature Conservancy, includes a modest arboretum, public beach, and nature trail. The land area around the bay is subject to intense development and disturbance from residential areas, a golf course, and recreation. Because of the natural features of the bay area and the district’s unique archeology, the Territorial Government has further designated Magens Bay Preserve as an Area of Particular Concern (APC).

Key biodiversity
A total of 41 species have been confirmed: …Brown Pelican, Brown Booby, Magnificent Frigatebird, Great Blue Heron, Little Blue Heron, Yellow-crowned Night-heron, Blue-winged Teal, Red-tailed Hawk, American Kestrel, Common Moorhen, Semipalmated Plover, Wilson’s Plover, Lesser Yellowlegs, Spotted Sandpiper, Semipalmated Sandpiper, Laughing Gull, Royal Tern, Common Tern, Scaly-naped Pigeon, White-crowned Pigeon, Zenaida Dove, Common Ground Dove, Brown-throated Parakeet, Mangrove Cuckoo, Smooth-billed Ani, Green-throated Carib, Antillean Crested Hummingbird, Belted Kingfisher, Caribbean Eleania, Gray Kingbird, Northern Mockingbird, Pearly-eyed Thrasher, Northern Parula, Yellow Warbler, Prairie Warbler, Blackpoll Warbler, Black and White Warbler, American Redstart, Northern Waterthrush, Bananaquit, Black-faced Grassquit. Two unconfirmed reports of a Black-bellied Whistling Duck occurring in summer 2006.

Non-bird biodiversity: A total of 7 reptile species and 6 amphibian species were reported in the TNC inventory. Green Turtles (Chelonia mydas) and Hawksbill turtles (Eretmochelys imbricate) have been seen in Magens Bay. Several endangered/threatened species are know to occupy the preserve including the Mute Frog (Eleuterodactylus lentus), found in the lower woodlands, and the plants Chrysophyllum pauciflorum, Bull’s Foot Orchid (Psychilis macconelliae), Egger’s Cockspur (Erythrina eggersii) and Bulletwood (Manilkara bidentata). Introduced terrestrial pest species include mongoose, feral cats, and rats.

Pressure/threats to key biodiversity
The site is jointly owned by the Territorial Government of the V.I. and The Nature Conservancy. The preserve has been designated as an Area of Special Concern and there has been some effort to restore the arboretum and archeological sites. However, the current use and development is oriented towards public recreation rather than conservation or education. Landscaping along the beach has not considered removal of invasive or exotic species and, in some sites, coconuts and corn have been planted. Development in the vicinity of the Preserve continues to increase the loss of soil stabilizing vegetation on the steep slopes above the preserve and has already resulted in erosion and runoff into the bay. Nearby corals in the bay have been negatively affected by sedimentation and show signs of bleaching. Mangroves in the lower wetlands are critical to the stabilization and filtering of slope runoff and are under growing threat from invasive plants (Sweet Lime, etc.) where disturbance and openings have occurred. Magens Bay opens northwesterly to the sea so there is a natural threat from tropical storms that could damage the beach, mangroves, or forests. Maintenance and restoration of the mangrove wetlands and beach area vegetation is vital to stabilizing and protecting these areas for both human enjoyment and wildlife use.

Conservation responses/actions for key biodiversity
The 2005 report “A Survey of the Plants, Birds, Reptiles and Amphibians at The Magens Bay Preserve, St. Thomas, U.S. Virgin Islands” documents a recent inventory conducted of the preserve. Ongoing land development and management by the DPNR continue in the arboretum and lower forest/agriculture areas and warrant a regular monitoring program in the preserve.

Protected areas
The entire Magens Bay Preserve is officially recognized and designated for protection.

Habitat and land use
Magens Bay Preserve contains 7 major vegetation community types: Dry Forest, Moist Forest, Wetland, Woodland, Shrubland, Cropland/Arboretum and Beach. Most of the forest exists on the steep upland slopes and the other vegetation types are in the low-lying basin. A total of 204 plant species in 69 families were detected and identified by Nature Conservancy survey. The wetlands vegetation includes both mangroves and mixed swamp in a very dense growth. The primary plant species are Red Mangrove (Rhizophora mangle), White Mangrove (Laguncularia racemosa), Ginoria rohrii, and Seaside Mahoe (Thespesia populnea). Although most of the area is subject to low human use/disturbance (wetlands, forest and trail), the area of the beach, parking areas, and access road is heavily used and has regular human presence and high level of activities. The beach is managed with an entrance fee that helps pay for oversight and maintenance that makes the site very popular.

Jim Corven

Recommended citation
BirdLife International (2023) Important Bird Areas factsheet: Magens Bay. Downloaded from on 27/03/2023.