With a choice between waking up with an alarm clock or radio, or waking to the songs of birds, the birds win hands down. Silent mornings have turned into a symphony of song as birds return from their winter retreats.
Whether flying across the continent or just a few miles, birds must negotiate a variety of dangerous structures. The skies are a veritable obstacle course of human-related hazards. The towers erected for our cell phones and pagers, the lines that bring us power, the windows on our homes and office buildings, as well as sources of renewable energy like wind turbines, create obstacles for birds in flight.
Biologists estimate that the combined death toll from aerial collisions may exceed 700 million birds each year, affecting all types of birds from ducks, gulls, plovers, owls and hawks to woodpeckers, hummingbirds, warblers, sparrows and finches.
Organizations, government agencies, communities and individuals are looking at the various causes of collisions and coming up with ways of making a bird’s journey safer. Even individual participation in such efforts can have significant results. Small changes at home, work and in a community can make a world of difference to conserving our wonderful bird life.
- Power Lines: Birds with large wingspans like hawks, eagles, cranes and swans are less maneuverable and thus are more vulnerable to collisions with power lines. Wind and storms also make avoiding these lines a challenge. New guidelines at utility companies are helping to lower the impacts. Burying power lines eliminates collisions. Flags or marker balls on lines located above ground increase their visibility, helping birds see and avoid them.
- Communication Towers: These towers provide coverage for cell phones, television and radio—all technologies that have become an integral part of our lives. More than 140,000 towers are in the United States and as many as 5,000 new towers are erected each year.
The towers that are most hazardous to birds are more than 200 feet high, illuminated at night with red lights, supported by guy wires, or located in migration corridors. Birds that migrate at night are drawn to towers lights, especially in poor weather. They become disoriented and circle until they eventually strike guy wires, the tower or even one another.
Birds are less likely to be harmed by shorter structures that require no lighting or guy wires, have lights that are green or white and towers that are located away from migration corridors. The creative placement of new towers includes using existing buildings.
Tall building and signs that remain lit all night are as hazardous as lighted towers. Birds may be attracted by these structures, become confused by the lights and circle them repeatedly, dying of exhaustion or colliding into the building
- Wind Turbines: Harnessing the wind’s energy to create electricity, wind farms may consist of hundreds of turbines: structures which support fanlike rotors connected to generators. Like communication towers, turbines are most harmful to migrating birds on cloudy nights and when turbine heights require the use of lights. New wind farms that consider bird migration routes and turbine height will help minimize bird fatalities.
- Plate Glass: One of the greatest hazards to birds is plate glass, with windows in homes and offices killing as many as one billion birds each year. Glass is invisible to birds and if they see the reflection of trees, bushes, the sky or natural habitats, a bird may fly directly into it.
The presence of houseplants behind windows, the distance of vegetation or bird feeders from windows and the angle of reflection may influence the likelihood of a bird flying into the glass.
Studies indicate that one out of every two strikes is fatal. If not killed outright, birds stunned after striking glass often fall prey to predatory birds, mammals and house pets. Even birds that survive an initial impact often die later from their injuries.
For information on bird and reducing collisions, contact:
- International Migratory Bird Day: http://www.birdday.org & 1-866-334-3330 or http://birds.fws.gov/imbd & 703-358-2318.
- Fatal Light Awareness Program: http://www.flap.org or 416-366-FLAP.
- American Bird Conservancy Wind Energy Policy: abcbirds.org or 540-253-5780.
- Birds and Buildings: 773-517-3657 or www.birdsandbuildings.org
Prevent Pane-ful Bird Collisions!
There are many ways to reduce bird strikes at windows:
- Hang ribbons, wind chimes or hawk silhouettes on suction cups on the full length of glass windows. Movement is more effective in deterring birds than static images.
- Place feeders, bird baths and plants less than 3 feet from a window so that birds are less likely to build up enough momentum to harm themselves.
- Place feeders more then 30 feet from windows so that the windows are not in the birds’ flight path when they fly to and from the feeder.
- Close curtains and blinds when possible.
- Use window films that lessen the glare and transparency of glass.
- Shut off building lights when not needed and/or draw blinds from dusk to dawn.