Developing a Bird-Glass Collision Monitoring Program

Every year, nearly a billion birds fall victim to fatal collisions with glass windows and lit structures across the country. These preventable collisions are not just about the loss of birds, they signify a larger ecological imbalance and highlight the need for more bird-friendly design and planning in our communities. Whether you are part of a conservation group, a concerned citizen, student or researcher, this toolkit is designed to help guide you through establishing a program with your peers to monitor, document, and address bird-glass collisions in your area. While we know that almost all glass and lights can cause bird collisions, monitoring for collisions can help document the problem for building owners and can help prioritize which glass to retrofit first. Monitoring for collisions is not necessary before retrofitting glass and turning off lights to reduce collisions.

Designing and Organizing Your Monitoring Program

Getting Started

Assemble a Team: Gather a team of colleagues passionate about bird conservation. While it is not necessary, it can be helpful to have individuals who are skilled in bird identification, data collection, and community outreach.

Define the Scope: Determine the area you can survey regularly. If documenting bird collisions is necessary to justifying glass and lighting changes or if data will be used to prioritize which glass to retrofit first, then include:

• large glass areas,
• areas near bird feeders,
• areas with light escape at night, and 
• known collision areas

Establish a Schedule: Ideally, glass will be searched every day throughout the year, both in the morning and afternoon. However, if you must limit your time commitment it is best to prioritize monitoring during spring and fall bird migration seasons when birds are most vulnerable. Searches conducted 5-6 times a week can also be effective, regardless of time-of-day. Peak migration months in the contiguous United States are April, May, September, and October. For additional details on bird migration specific to your area, visit IPaC or BirdCast. 

Gather Materials: we recommend a datasheet (see template in documents below), clipboard, pencil, permanent marker, sealable freezer bags, cardboard box for large birds, paper bags with paper towel for smaller birds, gloves, camera and bird ID resources.

Search Methods and Data Collection

1. Observers walk around glass areas (alternating directions on successive days) examining the ground for bird carcasses within two meters of glass surfaces. Be aware that injured birds may seek shelter under vegetation or other structures. 
2. Examine the glass for signs of collisions noting any powder, feathers, blood, etc. left behind by birds on the datasheet. 
3. If you find deceased birds, store them individually in a sealed freezer bag with the following data recorded on the bag using permanent marker: date, time, species (if known), location found, weather, and the observer’s name. The same information should be recorded on the datasheet. After the search is complete, dead birds should be placed in a freezer or donated to research or museums.
4. Live birds should be gently captured and safely placed in a labeled paper bag lined with a paper towel. Record on the paper bag and on the datasheet: date, time, species (if known, otherwise take photograph, if possible), location found, weather, and the observer’s name. Birds that survive collisions with glass often suffer from head trauma, neurological disorders, eye injuries, temporary blindness, and air sac punctures, which can often be treated at a licensed wildlife rehabilitation center. Because these symptoms can take more than 24 hours to appear, it is important to take injured birds to a licensed wildlife rehabilitation center as soon as possible. When capturing injured birds, approach them from behind and pick them up using a net, towel, or hands. Use caution when capturing large birds that may become defensive or aggressive. Consider wearing gloves and using cardboard boxes for containment. If you find an injured American woodcock, place them in a bag because they often reinjure their heads in boxes. Clip paper bags closed with binder clips or clothespins. Paper bags are breathable material and do not need air holes. Place bags and boxes in a safe location until birds can be transported to the licensed wildlife rehabilitator. Licensed rehabilitators can be found at National Wildlife Rehabilitators Association, Animal Help Now, or your state’s website for wildlife response.

Datasheet- Observers should complete the datasheet including the birds detected, signs of collision or "zero" when no signs of collision are detected. Be sure to complete the data entry for the time spent monitoring for collisions, as well as any relevant notes, or photos. Data can be entered into our online database (optional).

Permits- A Federal Migratory Bird Special Purpose Salvage permit is required to authorize you to collect dead migratory birds, nests, eggs and parts from the wild, including federal employees.  If you are a Service employee, you may be covered under your Regional Director's permit.  Many states also require a state salvage permit for activities that are off federal land. If you do not have a Salvage permit or other salvage authorization, you must leave any birds remains where they were discovered. If you find a sick, injured, or orphaned bird, you may transport it to a federally permitted rehabilitator or licensed veterinarian without a permit.

Interpreting and Using Data

Carcass searches will likely reveal problem areas with relatively higher numbers of bird collisions. Our Low-cost Methods to Reduce Bird Collisions with Glass and Bird Collision Reduction Toolkits provide useful information for treating glass to reduce bird collisions.

Start making your difference today! 

For more information, you may contact FWS Biologist Joelle Gehring at Joelle_Gehring@FWS.gov