Wrens
Wrens are small, active birds, basically brown in color, that often
perch with their tails held straight up. They forage on or just above
the ground in thick brush, forest understory or marsh vegetation. Wrens
belong to Family Troglodytidae, with about 70 species in the New World,
most of them in the tropics. Only one species lives in the Old World:
the winter wren, which likely spread from Alaska to Siberia and extended
its range westward until, eons in the past, it reached Britain and
Iceland. Some wrens nest in cavities; others build roofed structures out
of plant matter. The males of several species build "dummy" nests,
preliminary nests placed in tree cavities, woodpecker holes and nest
boxes, and less frequently in odd enclosed spaces such as tin cans,
pockets of clothing hung outdoors, hats, boots, flower pots and
drainpipes. Later, a female will choose one of the male's dummy nests,
finish its construction, and lay eggs in it. Wrens often pester other
birds and evict them from nest cavities, puncturing their eggs or
pecking their young to death. They destroy nests in cavities and in the
open; they also wreck other wrens' nests. Why such belligerence? Does an
abundance of empty nests discourage predators from looking further and
finding an active wren's nest? Or does killing its rivals' offspring
reduce pressures on prey populations, making it easier for a wren to
feed its own young?Wrens eat mainly insects and spiders. A few species will also feed on berries and seeds. Owls, small hawks and house cats take adult wrens; raccoons, opossums, minks, weasels, mice, squirrels, woodpeckers and snakes raid wrens' nests. Some wrens migrate southward in winter, while other species remain as permanent residents on their breeding range. Five species are found in Pennsylvania.
» Small buffy songbird.
» Tail often held upward.
» Rusty underparts.
» White eyestripe.
» Loud.
» Size: 12-14 cm (5-6 in)
» Wing span: 29 cm (11 in)
» Weight: 18-22 g (0.64-0.78 ounces)
» Sexes look alike; male slightly larger
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