Southgate and Green Cay

Country/territory: Virgin Islands (to USA)

IBA criteria met: A1, A2, B4i (2007)
For more information about IBA criteria, please click here

Area: 247 ha

Site description (2007 baseline)
Southgate Coastal Reserve (SCR) and Green Cay National Wildlife Refuge (GCNWR) are located in the northeastern sector of St. Croix, U.S. Virgin Islands (USVI). The Caribbean Sea surrounds Green Cay NWR and separates it from Southgate Coastal Reserve. Both sites are nominated as one IBA because of their physical proximity. Southgate Coastal Reserve, established by the St. Croix Environmental Association (SEA) in 2000, consists of 41.5 ha that encompasses a 13 ha salt pond (Southgate Pond), 7.7 ha of associated wetlands, 5.8 ha of littoral deciduous woodland along a beach berm, and 15 ha of upland grassland. Two intermittent watercourses (guts) cross the property. East gut runs near the eastern boundary line and empties into the Caribbean Sea. West gut runs through the center of the property and into the salt pond basin. A man-made causeway contains Southgate Pond (hereafter SP) on the western side and a beach berm on its northern side separates it from the sea. The salinity and depth of the pond fluctuate with rainfall and associated run off from 311 ha of the upland watershed. Except when overflowing, the maximum pond depth is about 1.4 m. A dirt track traversing the property from south to north just east of the pond is used to access the beach. One derelict condominium structure is located within the delineated wetland. SEA intends to demolish the condo structure and build an interpretive center and field station at a suitable location on the upland portion of the property. Green Cay Marina, which formerly comprised part of SP, is located just west of SCR and south of Green Cay. A gated community and Tamarind Reef Hotel are adjacent to the marina. Chenay Bay Beach Resort adjoins SCR to the east. Route 83, a desalinization company, a small organic farm and pastureland border SCR on the south. Low density residential housing occurs in this area. Green Cay, an uninhabited 5.7 ha cay, lies off the north coast approximately 400 m from SCR and Green Cay Marina. Green Cay is of volcanic origin and prominent geological features include lava outcrops, tuffs, and breccias. Green Cay is saddle-shaped, with high points at the northern (12 m) and southern (21 m) ends connected by a narrow valley eight meters above sea level. The cay is mostly surrounded by steep cliffs. A small beach is found on the southern tip of the cay and narrow stretches of cobble beaches are found along the eastern and western shorelines. Green Cay was designated a National Wildlife Refuge in 1977 to protect the largest remaining population of the critically endangered St. Croix Ground Lizard (Ameiva polops), as well as to protect important bird nesting habitat. Green Cay is administered under the Caribbean Islands National Wildlife Refuge Complex.

Key biodiversity
Surveys conducted by D. B. McNair, C. Cramer-Burke, L. D. Yntema and C. D. Lombard from 2002 to 2007 have confirmed 98 species of birds at SCR and GCNWR. Of these, 24 species have nested. The Brown Pelican was listed as a federally Endangered Species in 1970 and the Caribbean population remains listed today. During 2003 and 2004 Brown Pelicans nested on the western side of Green Cay. 54 nests were documented in 2003 and 64 nests in 2004. Newly fledged young are guided by adults to SP where as many as 76 juveniles have been observed feeding. Brown Pelicans and Magnificent Frigatebirds roost year-round in the trees, cliffs, and beaches of GCNWR and in the mangroves on the north side of SP. Least Terns, listed as territorially Endangered in the USVI, breed on exposed, unvegetated mud flats at SCR when the pond bed is dry. In 2003, a large breeding colony produced 357 nests (Lombard 2007). These nests were destroyed by feral dogs. In the following years when the pond bed was not completely dry, nesting did not occur at SP until 2006 when 7 nests were documented on dry mudflats (Lombard 2007). Seven Least Tern nests were also recorded on the south beach of Green Cay in 2006. Each year in August and early September, congregations of as many as 215 Least Terns feed and loaf at SP in preparation for fall migration. Caribbean Coots are listed as Near Threatened on the IUCN Red List and as Endangered in the USVI (U.S. Virgin Islands Endangered and Indigenous Species Act of 1990). Some Caribbean and American Coots breed in mixed pairs at SCR. A maximum number of four Caribbean Coot pairs have been identified during a nesting cycle. The maximum number of active nests of both coots has been 13, when about 9 breeding individuals were Caribbean Coots. The maximum population of Caribbean Coots present at SCR since 2002 is estimated to be 34 individuals. SCR has been identified as the most important site for Caribbean and American Coots in the USVI (McNair 2006a). White-crowned Pigeons are listed as Near Threatened on the IUCN Red List and as Endangered in the USVI. Although large colonies of White-crowned Pigeons are reported to have nested on Green Cay in the early 1920’s (McNair 2006b) and cays are generally favored breeding sites for columbids on St. Croix (McNair and Lombard 2006), in recent years no more than 6 breeding pairs of White-crowned Pigeons have been observed at GCNWR. One pair of American Oystercatchers, considered Threatened in the USVI, has nested annually on the shore of GCNWR. A maximum of 8 pairs of Wilson’s Plovers have nested annually from 2002-2007 on the dry mud flats, pond bed, and beach at SCR and along the shores of GC. Wilson’s Plover is considered a Species of Special Concern in the USVI. Twenty species of migrant shorebirds have been recorded on the beaches, mud flats, and pond fringes including Black-bellied and Semipalmated Plover, Greater and Lesser Yellowlegs, Spotted Sandpiper, Whimbrel, Ruddy Turnstone, Semipalmated, Least and Stilt Sandpipers, Short-billed Dowitchers, Wilson’s Snipe, and others. The Green-throated Carib and Antillean Crested Hummingbird, both restricted-range species within the Eastern Caribbean (A26), are frequently observed at GCNWR and at SCR. The Green-throated Carib nests at SCR and the Antillean-crested Hummingbird has nested on Green Cay. The Pearly-eyed Thrasher, also a restricted range species, occurs at SCR and GCNWR. Ruddy Ducks, considered a Species of Special Concern in the USVI, nested at SCR in 2005-2007 (McNair et al., 2006; C. Cramer-Burke, unpubl. data). Before 2005, the only documented nesting of Ruddy Ducks on St. Croix was during the first half of the 20th century (McNair et al., 2006). Other species confirmed nesting at SCR and GCNWR since 2002 have included White-cheeked Pintail, Pied-billed Grebe, Little Blue Heron, Green Heron, Common Moorhen, Killdeer, Black-necked Stilt, Zenaida Dove, Common Ground-Dove, Yellow Warbler, and Bananaquit. Great Blue Heron, Tricolored Heron and Black-Crowned Night-Heron, all considered Species of Special Concern in the USVI, are frequently seen at SCR or GCNWR. In early 2006 it was documented that over 100 Cattle Egrets were roosting nocturnally at GCNWR for the first time since 2001. Large groups of Great Egret (max 76), Snowy Egret (max 140), Little Blue Heron (max 47), Black-necked Stilt (max 170), Laughing Gull (max 250), and Royal Tern (max 28) feed at Southgate Pond when water levels are low and food is concentrated.

Non-bird biodiversity: The globally endangered St. Croix Ground Lizard, listed by USFWS in 1977, was once widespread and common in coastal areas but has now been extirpated from the main island of St. Croix, likely because of the introduction of the Small Indian Mongoose. Three small populations of this endemic lizard remain on St. Croix’s cays, Green Cay, Ruth Island, and Protestant Cay. The largest population occurs on Green Cay. In 2006, 61 probable Green Turtle (Chelonia mydas) nests, 42 probable Hawksbill (Eretmochelys imbricate) nests, and 10 probable Leatherback (Dermochelys coriacae) nests were documented at SCR. Nesting activities from Hawksbill and Green Turtles have also been confirmed at Green Cay.

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Southgate and Green Cay. Downloaded from on 24/09/2023.