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More than half of all living species of birds
are perching birds. Perching birds have been successful
in all terrestrial habitats. Typically small birds,
perching birds have a distinctive arrangement of toes
and leg tendons that enables them to perch acrobatically
on small twigs. They have the most well-developed and
complex vocalizations of all birds. They are divided
into two main groups: the sub-oscines, which are mainly
tropical and include tyrant flycatchers, antbirds, and
ovenbirds, and the oscines or songbirds, which make
up about 80 percent of all perching bird species, among
them the familiar sparrows, finches, warblers, crows,
blackbirds, thrushes, and swallows. Some birds of this
group catch and feed upon flying insects. An example
is the swallow, which opens its mouth in a large traplike
gape to gather food. One specialized group, the dippers,
is aquatic; its members obtain their food during short
dives in streams and rivers.
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