Cormorants, Shags (Family Phalacrocoracidae)
The bird Family Phalacrocoracidae is represented by some 40 species of
cormorants and shags. Several different classifications of the family have
been proposed recently, and the number of genera is disputed. In recent
years, three preferred treatments of the cormorant family have emerged;
the most widely accepted treatment is to leave all living cormorants in a
single genus, Phalacrocorax.
There is no consistent distinction between cormorants and shags. The
names "cormorant" and "shag" were originally the common names of the
two species of the family found in Great Britain. As other species were
discovered by English-speaking sailors and explorers elsewhere in the
world, some were called cormorants and some shags, depending on wheth-
er they had crests or not ("shag" refers to the bird's crest). Sometimes the
same species is called a cormorant in one part of the world and a shag in
another, e.g., the great cormorant is called the black shag in New Zealand
(the birds found in Australasia have a crest that is absent in European
members of the species).
Cormorants and shags are medium-to-large seabirds. They range in size
from the pygmy cormorant (Phalacrocorax pygmaeus), at as little as 45
cm (18 in) and 340 g (12 oz), to the flightless cormorant (Phalacrocorax
harrisi), at a maximum size 100 cm (40 in) and 5 kg (11 lb). The majority,
including nearly all Northern Hemisphere species, have mainly dark
plumage. The bill is long, thin, and sharply hooked.
Cormorants and shags are coastal rather than oceanic birds, and some have
colonised inland waters. All are fish-eaters, dining on small eels, fish, and
even water snakes. They dive from the surface, though many species make
a characteristic half-jump as they dive, presumably to give themselves a
more streamlined entry into the water. Under water they propel them-
selves with their feet.
Crooked Run Valley