Page 9 - Discover Summer 2021

Purple Martins
A Bird of a Different Feather
Common folklore hails the robin as a harbinger
of spring… and has as much scientific validity
as the groundhog’s shadow. With apologies and
all due respect to the “red, red robin”, if you are
looking for an early sign of spring, you will do
better to be on the lookout for a Purple Martin.
People react in surprise when they see a robin
on a cold day in January, because they assume that
they should be wintering in a warmer climate.
While some robins do migrate to the south in
the winter, their principal reason for doing so
is the search for food. In fact, many robins do
not migrate, and they often show themselves
in northern climes in the dead of winter. In the
colder months, they spend more time roosting
in trees, and thus less time digging for worms in
suburban yards.
The purple martin is a bird of an entirely
different feather.
Martins migrate to the tropics in the
wintertime, and for those who summer in
Virginia, the long migration begins as early as
Mid-July. This prolonged process may happen in
several stages, over a period of several weeks or
even longer. They travel to South America on a
5000-mile journey, stopping at large communal
“roosts” where they sleep at night. These roosts
are usually located near large bodies of water, but
sometimes they will be in clumps of trees, or even
in man-made structures in city and suburban
areas. Most of them are habitual stops for these
itinerant songbirds, usually chosen for their
By Tim Ernandes
relative warmth, and shelter from predators.
Purple Martins are extremely social creatures,
and although they always return to their “colony”
breeding sites, they generally do not travel in
flocks with the other members of their breeding
colonies. They seem to choose their traveling
companions at random, based on their travel
schedule. Their migration numbers are more akin
to swarms than flocks, often registering signatures
on Doppler radar screens. When they arrive at
their final tropical destination, purple martins
roost with other martin species, often in small
parks in and around cities.
The return journey is usually spearheaded by
the oldest birds, both male and female, who were
once thought to be “scouts”, who flew north in
search of suitable breeding sites for the colony,
and then returned south to guide the rest of
the flock to the chosen site. We now know that
martin colonies are random collections of birds;
their only connection to each other is a common
breeding site, to which they return faithfully. The
reason why the older birds arrive ahead of the
others is the intense competition for nesting sites,
and they have learned that the early bird gets first
pick.
In our area, one can expect to see the arrival
of the first Purple Martins around the middle of
March. Martins are insectivores, and they feed
in flight, so their migratory schedules will vary
to some degree with the weather, which in turn
will determine the availability of flying insects
www.discoversmithmountainlake.com 7