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Location Virgin Islands (to USA), St. Thomas
Central coordinates 64o 52.34' West  18o 18.90' North
IBA criteria A2
Area 225 ha
Year of IBA assessment 2007

Site description The site is located on the southeastern coast of St. Thomas and includes several mangrove cays (Bovoni Cay, Patricia Cay, Cas Cay) and lagoons (bays) around them. There is a protected cove on the northwestern side of Saba with a small sandy beach. Behind the beach is a relative open, flat area adjacent to the west pond. A nature trail was developed some years ago but has mostly grown over. A bird observation blind is located near the pond shore and overlooks the pond and vicinity. Offshore of both Saba and Flat Cay are modest sized coral reefs. The islands are publicly owned by the territorial government of the U.S. Virgin Islands and legally protected against terrestrial visitors during the seabird nesting season (April - October). Saba Island is vegetated by scrub-thorny brush and introduced guinea grass on the north facing slopes.

Key Biodiversity Observed in summer 2006: Brown Pelican, Magnificent Frigatebird, Little Blue Heron, Snowy Egret, Great Egret, Green Heron, Laughing Gull, Scaly-napped Pigeon, White Crowned Pigeon, Zenaida Dove, Common Ground-Dove, Green-throated Carib, Gray Kingbird, Yellow Warbler, Bananaquit, Lesser Antillean Bullfinch.

Non-bird biodiversity: Marine sponges, sting rays, small schools of fish, and an occasional barracuda or shark occupy the surrounding waters. There is a small cove at one outlet (“false outlet”) of the lagoon that has a good diversity of littoral sea life.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Green-throated Carib Eulampis holosericeus resident  2006  unknown  A2  Least Concern 
Antillean Crested Hummingbird Orthorhyncus cristatus resident  2006  unknown  A2  Least Concern 
Pearly-eyed Thrasher Margarops fuscatus resident  2006  unknown  A2  Least Concern 
Loxigilla noctis resident  2006  unknown  A2  Not Recognised 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Cas Cay/Mangrove Lagoon Marine Reserve and Wildlife Sanctuary 0 is identical to site 225  


IUCN habitat Habitat detail Extent (% of site)
Coastline   major
Shrubland Arid lowland scrub  minor
Sea   -
Rocky areas   -
Forest Mangrove  -

Land use

Land-use Extent (% of site)
tourism/recreation -
urban/industrial/transport -

Protection status Mangrove Lagoon and cays are protected habitats by the USVI Dept. of Planning and Natural Resources (DPNR) with restricted boat dockage and moorings. Access to the lagoons is open but limited to visitors with boats, kayaks, etc.

Acknowledgements Jim Corven

Further web sources of information 

Site profile from Important Bird Areas in the Caribbean: key sites for conservation (BirdLife International 2008)

References Boulon, Ralf H. & D. M. Griffin (1999);McLaughlin, M.(Eds)(1976); Platenberg et al. (2005) and Raffaele (1989).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Mangrove Lagoon. Downloaded from on 28/10/2016

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