Collision avoidance protects birds

As many as 1 billion birds die each year from collisions with building glass -- from skyscrapers to homes. Birds simply can’t tell reflection from reality. The American Bird Conservancy is stepping up its attention to this danger. Check out:  

This composite photo of birds killed at buildings in Baltimore is by Daniel Lebbin.

Category 3 of the basic requirements for being recognized as a Bird City is: Limiting or Removing Hazards to Birds. And one of those criteria asks that a "community provides easy-to-obtain information to property owners regarding protecting birds from window-strikes" -- that heartbreaking "thud" of a bird hitting one of our windows.

Here is some information to help you get started:

Collision with glass is believed to be one of the principal manmade causes of death for birds in North America. It is estimated that between 300 million and 1 billion birds are killed annually in North America by collisions with buildings – primarily by striking windows.  Last year alone the Wisconsin Humane Society admitted more than 200 birds who were involved in window collisions.

The Wisconsin Bird Conservation Initiative notes in one its study papers that birds collide with buildings both at night and during daylight hours.

Daytime Collisions - Birds do not see glass the way humans do - they do not realize that glass is an obstacle. Birds often see reflections of nearby vegetation or the sky on the glass and unwittingly attempt to fly into this false landscape. Especially dangerous are urban buildings with large windows within 40 feet of the ground, especially those surrounded by trees. Birds also collide with glass when windows align so that the bird can see into one window and out another window, creating a tunnel effect.  And birds sometimes are attracted to indoor vegetation, such as large potted plants inside a corporate building atrium, visible from outside through windows, and attempt to fly to and land on this vegetation, colliding with the glass.

Night-time Collisions - Bright lights from buildings – especially tall ones -- at night confuse birds, especially during rainy or foggy weather.  In Chicago and New York City, flocks of night-migrating songbirds numbering in the hundreds have been filmed circling in confusion around lighted skyscrapers and repeatedly colliding with lighted windows and building signage. Others circle these buildings until they drop, exhausted, onto the streets below. The next morning, the survivors may fall victim to urban scavengers or can't Audubon - Link to New York Audubon Resourcefind their way out of the canyons of glass, concrete and steel.

Growing awareness of light’s fatal attraction to birds has led to action: New York City Audubon inaugurated Lights Out NY in 2005. This year, a number of the city’s iconic buildings — the Chrysler Building, Rockefeller Center, The Warner Center and the Worldwide Plaza — will turn off their lights from midnight to dawn during peak migration season.

For More Information

Building Design Guidelines Now Available for Local Co-Branding

New Publication Provides Comprehensive Solutions to Halt Massive Bird Kills From Building Collisions

The cover of the new publication, Bird-Friendly Building Design

As part of a program to reduce the massive and growing number of bird deaths resulting from building collisions in the United States, American Bird Conservancy has produced a new, national publication, American Bird Conservancy’s Bird-Friendly Building Designs.


Organizations interested in co-branding this document and including local information and contacts, please email Christine Sheppard, Collisions Program Director, at



This would be an ideal step to take for communities seeking to meet Bird City Wisconsin's Category 3B criteria on window strikes.

See the WBCI website for more information on the impacts and solutions to the collisions issue. Click logo right.

Job is a window into threats to urban birds

Jim Stingl writes in the Milwaukee Journal Sentinel:
The job title alone made me want to shadow Renate Witt. She's a bird collision monitor. Renate is among a dozen volunteers who walk downtown streets early in the morning to look for birds that have flown into glassy buildings during the spring and fall migration seasons. Think bird watchers who look down instead of up. It's a situation when you'd rather not find what you're looking for.  Read the whole column by clicking the logo left

The American Bird Conservancy offers a downloadable flyer with great tips on how to reduce the chances of birds flying into home windows and glass doors. Click here for YOU CAN SAVE BIRDS FROM FLYING INTO WINDOWS

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