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SNAG TREES
A "snag" is a dead or dying tree suitable as a perch or
nest site or food source for wildlife.
While some snags occur naturally through disease; others
are created by foresters through thinning or crop tree
release. They are purposely left standing
to make homes and perches for birds and mammals.
There are at least 38 species of birds that either
excavate nest holes or use existing holes in dead or
dying trees. In addition, at least 29 species of
mammals also use tree cavities.
Snags serve birds in many ways. Woodpeckers and small
insect-eating birds find food on these dead or dying
trees. Birds of prey frequently use snags as
hunting perches. Many songbirds that occupy habitat on
the forest edge use snags as singing perches.
Woodpeckers often use resonant undecayed portions of
snags as drumming sites to signal their territory.
Primary cavity nesters, such as woodpeckers, typically
excavate their own nest sites. Secondary cavity
nesters, such as screech owls, use natural cavities and
abandoned woodpecker excavations.
Wildlife specialists have noted that snags are most
useful if they are at least 12 inches in diameter,
although some smaller birds use trees as narrow as 4
inches. Sometimes snags are left not for their size;
rather they were those crowding Crop Trees. Wildlife
specialists also have found that at least three snags
per acre is ideal.
Snags will eventually decay, fall to the ground, and
return their stored nutrients to the forest soil. |
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