Tuckernuck Island

It still retains remnants of the moraine as low hills, but the southern half of the island consists of outwash plains (sandur) characterized by coastal heathland, a globally restricted and endangered plant community.

There are extensive areas of scrub oak (Quercus ilicifolia) vegetation of up to 15 feet (4.6 m) in height, along with pitch pine (Pinus rigida), black huckleberry (Gaylussacia baccata) and sweet pepperbush (Clethra alnifolia).

Other plants include American beachgrass (Ammophila breviligulata), seaside goldenrod (Solidago sempervirens), poison ivy (Toxicodendron radicans), bayberry (Myrica pensylvanica), beach plum (Prunus maritima), saltspray rose (Rosa rugosa) and other shrubs on the stabilized dunes.

The largest concentration of Long-tailed Duck (Clangula hyemalis) in the western Atlantic occurs nearby (counts of over 150,000 have been recorded), along with thousands of common eiders (Somateria mollissima) and three species of scoter (Melanitta spp.).

Extensive sandspits on Tuckernuck are favored haul-out points for large numbers of harbor and gray seals (Phoca vitulina and Halichoerus grypus, respectively).