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MAY 2006 BIRD OF THE MONTH |
AS THE SWALLOWS
RETURN TO ….. THE FLATHEAD
Compiled by Linda deKort
CLICK HERE FOR .PDF VERSION
Like the legendary cliff swallows who loyally
return each year to the mission in Capistrano, California,
the swallows of the Flathead are arriving back
at their predictable times. We may not greet them
with the ringing of church bells, nor a huge fiesta,
but their return is no less remarkable.
Swallows belong to the family Hirundinidae.
All swallows forage for aerial insects
and spend more time on the wing than
any other songbirds in the world. Their
short wide bills help them feed as they
sweep through clouds of swarming insects
near water and above the forest
canopy. Many species roost at night on
marsh reeds.
Among the swallows that return here each spring to breed
are the Tree Swallow, Violet-green Swallow, Northern
Rough-winged Swallow, Bank Swallow, Cliff Swallow, and
Barn Swallow. Tree Swallows arrive first, about the
first week in April. Just a bit later we see the
Violet-greens. By the end of April the Northern
Rough-winged, the Cliff and the Barn Swallows are here.
The Bank Swallows are the last to arrive, early in May.
Our six species of swallows winter as far away as
Central and South America; they will head south again in
September. Until then, we have the opportunity to relish
the aerial acrobatics of these elegant birds and to
benefit from their mosquito hawking expertise. Swallows
eat insects almost constantly while in flight. For this
reason, attracting swallows may be one positive step to
managing insects such as flying ants, termites, aphids,
mosquitoes and gnats. On average, insects make up 99.8
percent of the swallow’s diet. A single Barn Swallow can
consume 60 insects per hour or a whopping 850 per day.
That’s 25,000 fewer insects per month that
might have joined your summer bar-b-que.
Barn Swallows (Hirundo rustica) provided
our family with our first close up and personal encounter
with the swallows of the Flathead. This article
is devoted to them. (Next spring, you can anticipate
an article on one of our other amazing swallow
species.) The Barn Swallow is the only North American
swallow with a deeply forked tail. The male's tail
is somewhat longer than the female’s and juveniles
don't develop the long tail until they reach adulthood
after one year. The male usually has a rich orange
breast and belly; the female has a whitish belly. Both sexes have a deep rust-colored throat and their upper
body glistens in iridescent blue-black. They are
about 5 to 7 inches long, and about 3/4 ounce. They
have slender pointed wings and their flight seems
easier and more flowing than other swallows. They
are also the fastest of the swallows and have been
clocked flying 46 mph!
Because of their preferred nesting sites,
Barn Swallows have undoubtedly provided
many families with opportunities
to view courtship, incubation and rearing.
Barn Swallows were originally cave
breeders but now build their nests of
mud almost exclusively under manmade
structures such as barn rafters
(hence their name), bridges and eaves.
If you have a window positioned just in front of a chosen nest site, you
are treated to the best of reality shows. Both parents
help with the nest building. As the parents pick up mud
and carry it in their mouths, they form it into small
pellets. If you look closely at a swallow nest, you'll
see many individual mud pellets, as many as 1,000, that
make up the nest. The open cup on the top of the mass of
mud is lined with feathers, horse hair, and other soft
items. It might take the parents a full week to
construct the nest, with no time off on weekends. The
pair seem to work from dawn to dusk with only a brief
rest in the middle of the day. The female lays four or
five brown-speckled white eggs. The incubation period is
about two weeks, and both parents take unequal turns
sitting on eggs and providing food for each other. The
female does most of the incubation. They both rest at
night beside each other in the nest, a picture of
contentment and loyalty. But don’t be deceived; there is
much more to the courtship of barn swallows than this
tranquil scene suggests. Science magazine reported last
fall that females constantly judge their mates by their
looks, in particular by the reddish color of the males’
breast and belly feathers. Females mated to males with
paler feathers were more likely to secretly
copulate with another male. Researchers from the Lab of
Ornithology of Cornell University used nontoxic markers
to enhance the feather color of some of the males in the
study. All of the swallows remained paired with their
original mates, but DNA testing revealed that females
paired to males with the reddest feathers cheated less. As a result, those males fathered
a greater proportion of young in their brood.
Perhaps the intensity of the reddish color is an indicator
of the male’s health, status, and ability to raise
young. The long tail of a Barn Swallow also may indicate
the quality of the individual bird; another study
revealed that females prefer to mate with males that
have the longest and most symmetrical tails. Unmated
male Barn Swallows have been observed
killing nestlings of nesting pairs, which often succeeds
in breaking up the pairs and affords the culprits
the opportunity to mate. So among barn swallows,
color matters and all is fair in love and war.
The young stay in the nest about 3 weeks after hatching. Both parents
provide care. The little ones, when fully fledged, are
enticed to fly by their parents. As the young improve in
flying, they are
often fed on the wing by the parent birds. In the
evening the family retires to the breeding place, and
usually stays there until mid- August when migration
activity begins. During this time, those beautiful mud-based
nests can become regarded as an
unattractive decoration, as the fledglings
drop their “calling cards” below. Despite this
annoyance, remember that not only are swallow
nests truly a sign of good luck, their inhabitants help
keep down the mosquito population. Swallows, their
active nests and eggs are protected by the federal
Migratory Bird Treaty Act and may not be destroyed.
If, however, you find a swallow nest being constructed
near your front door, try placing an artificial
nest off to one side of the door or even on a different
wall; it may be the surest way to coax the swallows
to move, because barn swallows seem to prefer a
distance of several feet between nests.
As you watch the swallows returning to Flathead
Valley this spring, consider their beauty, their
intrigue and their mosquito-eating fervor. Then get
out the bells and ring in their return.
Selections from Cornell University Website |
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