Bird-Window Collisions

Every year, millions of birds are killed when they fly into windows. For example, when they are near windows and get startled, they try to fly to nearby trees for cover. But if those trees are actually reflections in a window, they hit that window and are often killed. This is particularly problematic during migrations in the spring and fall.

Jin Bai, a New Hope Audubon board member and Chair of the Community Science Committee, recently organized a community science project at the University of North Carolina in Chapel Hill to assess the extent of the problem on that campus. He recruited a team of volunteers to make periodic visits to particular sites on campus and gather data on bird strikes. The protocol he designed can be found here. And here is his report of this year’s survey.

UNC-Chapel Hill Bird-window Collision Survey Report – 2021

I want to thank all of the volunteers who helped with the Bird-window Collision Survey
on the UNC Campus! Here is a summary of what we found. We had a total of 17 volunteers
who signed up on the google sheet schedule. We had survey efforts from 17 days during the
survey period (Sep 22 to Oct 12, 2021).

  1. We surveyed Davis Library 15 times with no collision observations.
  2. We surveyed the FedEx Global Education Center 14 times with 1 collision observation of a
    dead Veery.
  3. We surveyed the Frank Porter Graham Student Union 15 times with no collision
  4. We surveyed the Tate-Turner-Kuralt Building 17 times with 2 collision observations of a dead
    Black-throated Blue Warbler and a dead unidentified passerine.
  5. We surveyed Wilson Hall 13 times with 5 collision observations of an alive Common
    Yellowthroat, a dead Red-eyed Vireo, a dead Gray Catbird, a dead Ovenbird, and a
    dead White-eyed Vireo.

Here are a few of the pictures that were taken from the Fall 2021 collision survey and past collision observations (before Fall 2021) on the UNC-Chapel Hill Campus.

Magnolia Warbler – Photo by Allen Hurlbert

Ovenbird – Photo by Gina Calabrese

White-eyed Vireo – Photo by Jin Bai

In summary, we had 8 collision observations from 3 warblers (Parulidae), 2 vireos (Vireonidae),
1 thrush (Turdidae), 1 thrasher (Mimidae), and 1 unidentified passerine (likely a Red-eyed Vireo).
All collision birds we observed were migrants. Most observations came from Wilson Hall. I will
give an update again when we use the data collected to convince building managers to
implement mitigation strategies. The iNaturalist project of “Bird Collisions at UNC-Chapel Hill”
will be continuing to collect collision observations. Everyone is welcome to submit collision
observations to this project wherever you go on campus. I am greatly appreciative for all the
volunteer efforts!

Click here to download a spreadsheet of the data collected this year.

The protocol for the bird-window collisions survey on the UNC Campus

(The following protocol is adapted from the Window Collision project at Duke University.)

Survey period: Fall 2021 (Sep 22 to Oct 12, 2021).

Survey time: 12 to 6 pm every day during the survey period.

Survey locations: 5 buildings on UNC Campus.

  1. Davis Library
  2. FedEx Global Education Center
  3. Frank Porter Graham Student Union
  4. Tate-Turner-Kuralt Building (School of Social Work)
  5. Wilson Hall and breezeway

Data collection protocol:

  1. During each survey, the observer will walk the entire perimeter of the building, looking for bird carcasses or injured birds in a 2-m search from the building wall.
  2. If carcasses or injured birds are found, the volunteer will take pictures of the bird from all angles and make sure the field marks of the bird are visible from the pictures. Then volunteers will upload their pictures on iNaturalist and assign their observations to a project called “Bird Collisions at UNC-Chapel Hill”. If volunteers have difficulties using iNaturalist, please email the pictures to Here’s how to use iNaturalist. In order to assign your observation to an iNaturalist project, you need to join that project first.
      (1) If you are using the mobile app of iNaturalist, click “more” and then click “Projects”. Then use the search button to type in “Bird Collisions at UNC-Chapel Hill”, then click “Join”. Now, when you make a new observation on iNaturalist, you can click on “Projects” and choose “Bird Collisions at UNC-Chapel Hill”.
      (2) If you are using the website of iNaturalist, you will need to search for that project from the upper left corner on the main page when you log in and then join the project, then you will be able to assign your observation to “Bird Collisions at UNC-Chapel Hill”.
  3. If no carcasses or injured birds are found, skip to the next step.
  4. The final step is to fill out a google form survey to submit your survey result.
  5. If you find bird carcasses or injured birds outside of the targeted 5 buildings, please submit your data through the above google form as well.

Volunteer Signup Schedule
If you are interested in helping to survey bird-window collisions on UNC Campus, please sign up on this google sheet. Thank you so much for your help!!

Information about parking and visiting UNC Campus
A parking permit is not required on UNC Campus from Friday 5 pm to Mon 7:30 am every week. Volunteers who are not UNC students or employees can survey the buildings on the afternoons of Friday (after 5 pm), Saturday, and Sunday by car. However, surveying these buildings by foot, bus, and bicycle is recommended. A free bus route of RU drives through 4 of the 5 survey locations.

Information about collecting bird carcasses
Volunteers can collect and freeze the dead birds for the bird specimen collections at the North Carolina Museum of Natural Sciences. Please put the carcass in a ziplock with a piece of paper indicating the date, location, species, collector’s name, and cause of death. Then put the ziplock in a cooler and bring it to the North Carolina Museum of Natural Sciences front desk.

Information about injured birds
If you find an injured bird from a window collision, please visit for more information about bird rehabilitation.

Contact information for this project
Jin Bai
Community Science Committee Chair
New Hope Audubon Society

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