The site is a peninsula of land approximately 2.5 kilometers long. Fort Amsterdam is a registered historical site, composed of several ruins. The pelican breeding colony is located on the west side of the point, on a slope below the fort. Vegetation is characterized by thorny scrub, composed mainly of Acacia macracantha and A. tortuosa, reaching over 2 m in height. The colony was on the western side of the point, below the fort. A smaller group of about 10 pelicans has also nested on the eastern side of Fort Amsterdam.
The breeding population of Brown Pelicans at Ft. Amsterdam varies greatly between years. The highest count was 60 nests in 2001, which qualifies as regionally important to the Caribbean Brown Pelican population. The presence of nesting pelicans at Pelikan Rock is noted in the literature, but no mention of the Fort Amsterdam colony has been found (Danforth 1930; Voous 1954, 1955a, 1955b, 1983; Voous and Koelers 1967; Pinchon 1976; Hoogerworf 1977; Halewyn and Norton 1984; Rojer 1997; Raffaele et al. 1998; Collazo et al. 2000). The only exception is a note by David Johnston from the same year as the initial sighting in 2001 (Norton and White 2001). The size of the Fort Amsterdam colony would seem to make it more obvious than the smaller and more distant Pelikan Key colony. The area may have been overlooked in the past or possibly it was recently colonized. Regionally limited species found at this site 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 island endemic Anolis pogus may be present at this site.
BirdLife International (2019) Important Bird Areas factsheet: Fort Amsterdam, Sint Maarten. Downloaded from http://www.birdlife.org on 23/08/2019.