Saba Coastline includes all areas from the waterline to 400 meters inland around the perimeter of this small island. Because Saba’s coast is composed solely of cliffs, Red-billed Tropicbirds can be found all around the island. This habitat also is appropriate for Audubon’s Shearwater, a species which is much more difficult to detect but breeds on the island. The IBA should include Rainforest Ravine, part of the proposed Saba National Land Park, the only site where nesting of Audubon’s Shearwater has been confirmed in recent decades. The only human settlements along the coast are at Fort Bay, where a dock, several buildings, a rock quarry, and landfill exist. It is also a Tropicbird research site.
The Saban population of Red-billed Tropicbirds has been estimated at 750-1,000 breeding pairs, meeting the requirement for more than 1% of the global estimated population (20,000). They can be found nesting around the entire perimeter of the island in coastal cliffs and xeric, rocky hills. Despite being the national bird of Saba and familiar to residents, the Audubon’s Shearwater population is much more difficult to estimate accurately due to inconspicuous nesting habits and inadequate data. Because all coastal areas are cliffs, there is a tremendous amount of potential habitat. Indeed Lee (2000) has placed the population at 1,000 individuals based on available habitat. One shearwater was found on an egg near Sulpher Mine in February 2002. No calls were heard during 10 hours of nocturnal observations in February (Collier et al. 2002). In April 2004, two hours of nocturnal call-playback resulted in one response by a shearwater near The Bottom. In May 2004, four hours of nocturnal call-playback resulted in three responses near The Bottom and 15-20 responses at Sulpher Mine. It is possible there is no peak in breeding activity, resulting in a protracted nesting period, which would further hinder population estimates. The steep topography limits accurate nest counts as well, although numbers of flying or calling adults may be used. Although these are the only known estimates, there is sufficient evidence to conclude that Saba meets the globally important criteria for Audubon’s Shearwater. Some regionally limited species can be found in pockets of habitat along the coastal zone, these include: Green-throated Carib Eulampis holosericeus, Antillean Crested Hummingbird Orthorhyncus cristatus, Pearly-eyed Thrasher Margarops fuscatus, and Lesser Antillean Bullfinch Loxigilla noctis.
Non-bird biodiversity: The single endemic vertebrate is Anolis sabanus. The gecko Sphaerodactylus sabanus has a restricted range. Hunting has caused The Mountain Crab Gecarcinus ruricola to now be considered endangered on the island. The bat sub-species Natalus stramineus stramineus is endemic to Saba.
BirdLife International (2021) Important Bird Areas factsheet: Saba. Downloaded from http://www.birdlife.org on 24/09/2021.