Migratory birds are an awe-inspiring sight when they flock high above us on their way to distant
lands. But their numbers are dwindling, largely because of the sweeping effects
human beings are having on the planet. By making a few changes in your garden
and community, you can help increase the odds that migratory birds will arrive
safely at their destinations.
There are more than 200
species of
migratory birds in the Western Hemisphere. These
include neotropical songbirds, hawks, shorebirds and waterfowl. Although we tend
to think of springtime and fall as bird migration times, those are just the most
common ones. In fact, at any time of year there are birds migrating. Often
migrations are made at night — particularly by songbirds — so we frequently don't
even witness them.
During bird migration, many species perform feats of strength and endurance that
have few parallels elsewhere in the animal kingdom. The ruby-throated
hummingbird, for example, which weighs all of 4 ounces, uses less than a single
ounce of fat to travel its 500-mile nonstop journey across the Gulf of Mexico.
The Artic tern, meanwhile, migrates 10,000 miles each way between the
northernmost part of North America and Antarctica, where it spends its winters.
Since the 1960s,
migrating flocks have declined by about 50 percent, and scientists attribute that decline primarily to two main
reasons:
- Habitat destruction. Human beings are clearing forests, draining wetlands and
removing critical habitats necessary to migratory birds both for resting places
along their migratory routes and as their seasonal destinations. The clearing of
Central and South American rain forests to plant sun-grown coffee plantations,
for example, is one of the principal culprits behind the loss of shady forests
long favored as winter habitats by migrating birds. Fewer forests and wetlands
along the way, meanwhile, mean that migrating birds may have to fly longer and
harder before finding a suitable
migration stopover point. Combined with the associated
scarcity of food and humans' frequent use of
toxic pesticides,
there is simply less nurturing habitat for migratory birds.
- Manmade obstacles. Brightly lit communications towers and tall office
buildings that twinkle like stars at night often confuse and disorient
migrating birds, since many depend on the constellations for their
navigation. As a result, they may circle for hours until they become
exhausted, placing them at risk of predation and death. Millions of
migratory birds
are killed each year by communications towers alone, according to the U.S. Fish
and Wildlife Service. Collisions with highly
reflective windows, meanwhile,
are estimated to kill more than a hundred million migrating birds each year.
The bottom line is that as many as half of all migratory
birds will not return to their
breeding sites in the spring. With their numbers already on the decline,
migratory birds increasingly need your help to survive.
-
Evaluate your yard for what migrating birds
need: Food, water and shelter. A birdbath or
shallow dish of water along with berry-producing
trees and shrubs can go a long way toward supplying the first two
requirements, and they may be supplemented by bird
feeders and cut fruit. Ideally, you should
populate your yard with plants that flower and
fruit throughout the spring, summer and fall, and
you should banish all
pesticides from your garden. For shelter,
evergreen trees and brush piles are among the most
valuable for migrating birds, as well as for other
small wildlife. The Humane Society of the United
States offers specific instructions for creating a
good
brush pile,
which is also a good source of food for
insectivores.
- Consider turning the roof of your house into a
"green
roof" topped with a variety of food- and
shelter-providing plants. Already popular in
Europe, green roofs are now emerging in North
America, and can help provide migratory birds with
more stopover points.
- If you drink coffee, choose shade-grown
varieties, which are produced without clearing
critical forest habitats. The
Atlanta Audubon Society and
Eartheasy
offer guides to producers and merchants of
shade-grown coffee, and the
Smithsonian Migratory Bird Center offers a look-up tool to help find shade-grown
coffee in your area.
- Nonreflective window coatings, window screens,
awnings, flash tape, bird netting and trees
planted nearby can all help block the sun and
make
windows less reflective,
minimizing the chance of collisions.
Bird feeders
should be moved away from windows to help slow
birds down and reduce their potential impact.
- Work to minimize the impact of brightly lit
office buildings and skyscrapers in your area by
encouraging building management and cleaning staff
to turn out the lights at night. The ubiquity of
communications towers is a problem that must be
addressed on a community level, and the
American Bird Conservancy has recommendations and information that can help.
