|
|
|
|
September 1997
Hawks awe me. Like all predators, they live on the edge of survival.
Each prey they catch is a reprieve from starvation.
To reduce competition for food among hawk species, each has different
prey they prefer, different ways of hunting for prey, or different types of
landscape they use. Wings,
eyes and feet of each species are specially designed for success with its prey,
hunting method, and habitat. Hawks
can pick out their prey at a distance two to three times farther than a human
could see the same object.
A great event in hawks’ annual cycle is migration.
The fall hawk migration is upon us, from September through November.
The whole point of migration is to increase the chances for survival of
the migrating species. In Maine’s
winter, snow and ice, extreme temperatures and lack of suitable food make
migration necessary for many types of birds, including hawks.
Hawks east of the Mississippi move from their northern summer nesting
areas to the Atlantic flyway, where birds of the same species gather together
and fly south. This flyway
between the Appalachian Mountains and Atlantic Ocean provides the updrafts
needed for hawks to soar and glide, conserving their own energy and making long
trips possible. The updrafts are
created by the sun warming the air. If
the weather is bad at any point during the journey, birds have to wait until
conditions change to continue their migration.
Migrating birds, including hawks, may use magnetic fields, the sun, and
the stars to determine direction and to navigate.
They may also use barometric pressure, changes in gravitation and
familiar landmarks such as mountain chains .
I had a conversation about hawk migration with Tom Hayward, a very
knowledgeable Lewiston bird enthusiast.
Tom is member of the Stanton Bird Club, and has watched hawk migrations
on Mt. Desert Island as well as Mt. Agamenticus in York County.
He told me about the the Bird Club’s
field trip to Mt. Agamenticus planned for this fall.
You may contact Tom at 782-5238 for information on the Club’s field
trips. There are also places
nearby to watch hawks as they begin the journey south.
The summit at Bradbury Mountain State Park on Rte. 9 in Pownal is one
such place. Harpswell, Freeport,
Swan Island in Merrymeeting Bay, and Hermit Island near Phippsburg are other
locations for sighting hawks on the move.
Broad-winged hawks, common in Maine, are long distance migrants.
With further to go, these hawks migrate relatively early, starting in the beginning of September.
They have all left by early October.
Nesting all over the US and into Canada, almost the entire
population heads south to Central America and
Bolivia and Peru in South America. While
migrating south, they form great flocks.
Sharp-shinned hawks, the smallest in Maine, are medium distance migrants,
wintering in Central and South America.
They begin migration at the same time as the broad-winged hawks, but the
period of migration extends until the end of October. They also migrate in large flocks.
Red-tailed hawks, another type of hawk seen frequently, are short to
medium distance migrants, travelling as far south as Panama in Central America.
They begin leaving Maine in mid October.
The largest numbers are on the move in early November, with numbers
dropping off toward the end of November.
The
individual hawks who stay the winter, for we do see them,
make that choice for reasons at which we can only guess. These hawks may be hardy, or foolhardy from the inexperience of youth.
As winter drags on, they are
attracted to where there is prey, for example, at our feeders.
They may use habitats not generally preferred, because they are hungry.
Red-tailed hawks are flexible in their diet, but eat mostly rodents.
Sharp-shinned hawks live mainly on small birds, although in my yard they
often target pigeons. When
people talk to me about the hawks eating small birds at their feeders, I explain
that the hawks take only what they need to survive.
Placing feeders ten feet from trees or shrubs would offer hiding cover to
small birds. The great threats to small birds, as well as to hawks, are
environmental pollutants and habitat destruction.
As you keep your eyes peeled for migrating hawks, don’t forget the
other migrants such as hummingbirds. All
migrants need to store fat reserves to make the long trip to their wintering
grounds. Keep your hummingbird
feeders going until early to mid October. The
sexes may migrate separately, with male hummingbirds leaving first, followed by
the females with the young. Changes
in things like the length of day and the angle of the sun trigger the migration,
so your feeders won’t entice them to stay too long.
Migration is one of the great pulses in wildlife cycles.
We can share some of the excitement and vitality of this adventure by
being observant and learning more. Timing,
skill and luck are important in
successful migration, much as they are in life.
By Nancy Coverstone (ncstone@umext.maine.edu), University of Maine Extension Educator in Androscoggin and Sagadahoc Counties
Return to Wild About Nature Table of Contents
Putting knowledge to work with the people of Maine
A Member of the University of Maine System
Last Modified:
08/13/06
These pages are currently being maintained from the
Communications Office Office, University of Maine Cooperative Extension.
Send comments, suggestions or inquiries to www-questions@umext.maine.edu
COUNTY OFFICES | PROGRAMS | RESOURCES | PUBLICATIONS | WHAT'S NEWS | UMAINE EXTENSION HOME | UMAINE
Information in this web site is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned in this web site. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.
