We all know that disheartening sound: a

bird smacking into a window in our house

or office building. The fact that birds strike

our windows every day is not only sad, it's

serious: more birds die because of

collisions with glass than any other factor

associated with human activity. Anywhere

from 100 million to 1 billion birds are killed

by window strikes each year. These strikes

account for the death of up to 5% of the fall

bird population. As the number of our

homes and offices continues to grow, the

number of bird deaths is likely to increase

as well.

Why Do Birds Fly Into Glass?

Windows allow us an opening into the

natural world outside. Unfortunately, the

glass which is a portal for us is actually a

barrier to birds. Both tinted and clear

glass are invisible to birds, who see a plant

or tree in the reflection of a window,

misinterpret it as safe haven, and fly

toward it. The placement of leafy green

plants inside a window seems to increase

the risk of collision. Another hazardous

situation occurs when one pane of glass

faces another, which creates an illusion of a

passageway through a structure. The

extra momentum gathered as the bird

attempts to "pass through" is especially

deadly.

The Danger of Plate Glass

Understanding and Avoiding

That Painful Thud

International

Migratory Bird

Day (IMBD),

held annually

on the second

Saturday in

May, is an

invitation to

celebrate and

support

migratory bird

conservation.

IMBD Information

web - http://birds.fws.gov/imbd

phone - 703 /358-2318

IMBD Materials

web - http://www.BirdDay.org

phone - 1-866/334-3330

March 2005

Tall buildings pose a special threat at night

because of their artificial lights, which

attract birds as they migrate. Bird

collisions are especially high during

periods of bad weather, including fog, low

clouds, and rain. Other factors which can

increase the number of birds flying

through urban areas (and crashing into the

glass surfaces there) include strong winds

and sudden changes in temperature.

Glass is dangerous in structures of all

sizes, including homes, schools,

storefronts, offices and apartment

buildings. It is also lethal in every season.

City skyscrapers result in the biggest kills

at night during the spring and fall

migrations, when the lights of tall

structures confuse birds on their flight

path. However, Klem reported that most

birds are actually killed during the day in

winter, when birds are attracted to the bird

feeders set up by approximately 25% of the

North American population.
What Happens When Birds Fly into Glass?

Although the sound of a bird hitting one of

our windows may be a familiar one, the

actual discovery of dead birds lying

beneath our windows is somewhat less

common. The fact that relatively few dead

birds are discovered is misleading,

however, and the resulting belief that most

birds can survive a window strike is false.

Klem estimates that one in two birds who

collide with glass will die as a result.

Typical injuries include broken beaks,

feathers, and head trauma.

The deceptively low numbers of dead birds

found underneath problem windows may

largely be due to the ability of predators

(cats, dogs, raccoons) to quickly seize a

dead or injured bird before we have even

seen it. The decorative shrubs and plants

which surround our homes make their

discovery even more difficult. Birds may

survive the initial impact, fly off to a safe

area, only to later die of injuries sustained

in the collision.

What Can We Do to Keep Birds Safe?

Make glass visible. If birds realize that

the glass barrier exists, they are able to

avoid it. There are different ways to help

birds see glass, ranging from the extreme

(whitewashing, etching or sandblasting) to

the moderate (hanging sun ornaments or

other materials). The popular solution of

hanging hawk silhouettes in windows is less

effective than moving pictures or ribbons.

Specialty products, such as Wing Chimes

and CollideEscape (film which covers a

window while preserving the interior view)

are available at a web site devoted to glass

safety (www.flap.org). Even the simple acts

of closing blinds, drawing drapes, and

turning off lights at night have been proven

effective in reducing window strikes.

Create barriers. A barrier between the

bird and the glass may prevent birds from

colliding. External sun shades and soccergrade netting are both effective ways of

keeping birds in flight away from a window.

Consider placement when attracting

birds. People can also make a difference by

putting their feeders and birdbaths in safe

locations. Several studies show that

feeders should be placed either very close

to a window (less than 3 feet) or far away

(more than 30 feet), so that the feeders are

not directly in the birds' flight path when

they fly from the feeder. Using window

feeders prevents birds from gathering

deadly momentum even if they do strike

the glass during their flight.

Explore innovations in new construction.

Windows that are adjusted in angle are

safer in new buildings; studies show that

even a 20 degree angle significantly lowers

bird fatalities. New windows can also be

modified in appearance, such as the glass in

the new observation tower in Niagara Falls

State Park, which has a striped pattern to

help increase its visibility for birds.

Another experiment in such technology is

the Swarthmore project, where builders

are installing panes which use tiny dots of

opaque glass to achieve a semifrosted look.

Support Lights Out Programs. Turning

off lights at night in buildings and homes

prevents the birds from being attracted to,

or confused by illuminated windows. An

example of city-wide success is the "Lights

Out" program voluntarily adopted by most

of the major skyscrapers in Chicago. Since

the buildings began dimming or turning off

lights, bird deaths during migration season

are estimated to have dropped by as much

as 80 percent. Similar programs are being

studied and at least partially implemented

in areas of New York and Toronto.

What Can I Do if a Bird Crashes into my

Window?

Despite our best efforts, birds will continue

to fly into glass in our offices and homes. If

you find a bird that has been killed or

injured by such a collision, you should use a

towel to cover and catch the bird, and place

it in a paper bag or cardboard box that can

be closed or covered securely (be sure to

provide airholes). Keep the contained bird

in a warm, dark and quiet place away from

noise and activity. Check on the bird every

half-hour, but do not handle it. If it seems

to recover, take the container outside and

set the bird free. If it does not recover

within a few hours, contact a wildlife

rehabilitator.

There are several ways to find your

nearest rehabilitator. Contact:

• Your local animal shelter or division of

the Humane Society,

• Your local veterinarian,

• Your state Division of Natural Resources, or

•The National Wildlife Rehabilitators

Association at (320) 259-4086, or the

International Wildlife Rehabilitation

Council at (408) 271-2685.