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In-Depth Information
Aegithalos caudatus
, feed almost exclusively on small insects and spiders. They
move around in large groups, traveling from tree to tree and hanging from
branches in their search for insects and at night huddling together for warmth.
Medium-Sized and Large Land-Based Birds
Birds around the size of a pigeon and larger often move in different ways
from smaller birds. When on the ground they have a tendency to walk or
run rather than hop, though some use a combination of all three methods
of locomotion. As we have already seen, an increase in a bird's size means
that flapping a wing requires more energy in larger birds; therefore flapping
is generally much slower in birds such as a pigeon or crow. However, the
increase in wing size makes these birds more capable of gliding over greater
distances and even of exploiting thermal uplift to achieve a soaring mode of
flight.
FIG 4.43
Medium-sized birds favor walking on the ground to hopping.
Some large birds still choose to move around in large groups, but they are
far less susceptible to the changes in weather and are therefore less likely to
huddle together for warmth during cold spells. The obvious exception to this
