THE BIRDS 215 
domesticated state, but the two beautiful wild swans found 
in this country are rarely seen. 
201. The herons and bitterns (Herodines)—The herons 
and bitterns are also aquatic in their habits, but, unlike the 
swimming-birds, they seek their food by wading. Adapting 
them for such an existence, the legs and neck are usually 
very long, and the bill, longer than the head, is sharp and 
slender. Among the relatively few species in the United 
States, the great blue heron (Ardea herodias) is widely dis- 
tributed, and may often be seen standing motionless in 
some shallow stream on the lookout for fish, or it may 
wander away into the meadows and uplands to vary its diet 
with frogs and small mammals. Even more familiar is the 
little green heron or poke (.4rdea virescens), which also is 
seen widely over the country. The night-herons, as their 
name indicates, stalk their prey by night, and during the 
day roost in companies—a characteristic common to most 
herons. The bitterns or stake-drivers are at home in reedy 
swamps, where they live singly or in pairs, and throughout 
the night, during times of migration, utter a booming noise 
resembling the driving of a stake into boggy ground. As 
a rule, the herons breed as they roost—in companies—build- 
ing bulky platforms, usually in trees. The bitterns, on the 
other hand, secrete their nests on the ground in the rushes 
of their marshy home. 
202. Cranes, rails, and coots (Paludicole).—In their ex- 
ternal form the cranes and rails resemble the herons, but 
in their internal organization they differ considerably. 
They likewise inhabit marshy lands, but usually avoid 
wading, picking up the frogs, fish, and insects or plants 
along the shore or from the surface of the water. The cranes 
are comparatively rare in this country, yet one may occasion- 
ally meet with the whooping-cranes (Grus americana) and 
sand-hill cranes (Grus mexicana), especially in the South 
and West. They are said to mate for life, and annually 
repair to the same breeding-grounds, where they build their 
15 
