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BIRD COLUMN FOR Jan 7, 2007
By Benjamin P. Burtt
The first bird to
nest in the spring is the great horned owl. Its courtship begins any day now
with lots of hooting and continues until the eggs are laid in mid-or
late-February.
These owls do not make a nest
of their own, but take over the old nest of a hawk, usually a red-tailed hawk
or they may select a nest that was used by
a crow or a squirrel. They seldom add any material. Once they have selected the site, they
will spend some time around it as the moment for egg-laying approaches. The
female will even sit in the nest before the eggs are laid. These used nests are not
always in good condition. They sometimes fall apart from wear and tear and
the effects of storms. If there is no
acceptable nest in the woods they have
used in the past, they will have to move to another patch of woods to find
another nest. It takes about a month to
hatch the eggs. Doing this in the winter the owls must contend with cold
weather and snow. The female must stay with the eggs and the male brings food
to her. When the eggs hatch, the male must find food for his whole family. The female stays
with the young, keeps them warm and tears up prey brought in by the male.
While she is incubating eggs or caring for small young she is sometimes
completely covered by snow. Most songbirds that nest in
warm weather do not start incubation until all the eggs are laid. Thus all young hatch at the same time. For the horned owl, incubation must
start with the first egg to keep it from chilling. So the eggs hatch at
intervals of a day or two. At a given moment the nestlings will be of
different sizes. The great horned owl is a
large bird. The distance from wing tip to wing tip is over 4 feet. The eyes
face forward as do human eyes and the owl can judge the distance to its prey.
Its eyes are large, about the size of human eyes and admit a lot of light
that helps it to hunt when the illumination is poor. So important are its eyes that they occupy
a space in its skull that is about twice that taken up by its brain! |
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