137
vascular plant species, 25
fungi and
lichen species, 44
mosses and
liverworts and 30 species of
algae have been recorded at Noss. Two nationally scarce species of vascular plant,
small adder's-tongue and
northern knotgrass are found here, as is the nationally scarce lichen
Lecanora straminea. The island is renowned for its seabird colonies and is one of the more accessible of the internationally important seabird colonies in the North Atlantic. The
sandstone cliffs of Noss have weathered into a series of horizontal ledges making ideal breeding grounds for
gannets,
puffins,
guillemots,
shags,
black-legged kittiwakes,
razorbills,
northern fulmars and
great skuas. The species profile has changed considerably over the last 100 years, with dramatic increases in some species and population crashes in others. Four new species have begun to breed here (gannet, fulmar, great skua and storm petrel), however a further six species that were formerly recorded (
lesser black-backed gull,
common gull,
tree sparrow,
Eurasian whimbrel,
peregrine falcon and
white-tailed eagle) no longer breed at Noss. In total 201 bird species have been recorded: in addition to the many seabirds several species of
waders also breed here, including
dunlin,
common snipe,
oystercatcher and
ringed plover. Other breeding bird species include
skylark,
meadow pipit,
rock pipit and
wheatear.
Otters are also frequently seen around the island, and
grey and
common seals are seen in small numbers. In total ten species of
cetacean have been seen in the seas off Noss, of which the most commonly recorded is the
harbour porpoise. ==Conservation designations==