This blog post will be featuring and discussing one of my current research projects, bird collisions on a large college campus in the Midwest, at the University of Illinois Urbana-Champaign. According to Loss et al. in 2014, up to a billion birds die each year from window strikes, one of the top three leading causes of bird mortality around the world. In this post, I will give some quick introductory information about the project, discuss some preliminary results from this year, then compare some results to the past few falls. This is an initial post and likely will post one or two more times in the future discussing the project and our finding smore in-depth, trends that we are seeing, along with updates on the project as a whole. This is just sharing the data alone at the current time. During our season this year, we found over 130 fatal strikes across 18 buildings during the season, over 250 for the fall as a whole, and over 300 across the campus (I continuously checked some other buildings).
The UIUC Bird Strike Survey was started in the Fall of 2019 by graduate students within the GEEB RSO here on campus, most notably by Alec Luro and Sarai Stuart. GEEB ran this project during the Falls of 2019 and 2020 and had three routes on campus. During 2020, they discontinued the Main Quad Route due to the fear of lack of participants because of covid before the season with making sure the most problematic areas on campus were continued to be covered thoroughly (North and South Quads). Emmarie Alexander and myself took over this project in early 2021 and created a spring season to study birds that strike during the spring migration, although since I will only be talking about fall data in this post, I will talk about our spring season sometime at a later date.
The prior students designed the season to encompass the peak of migration in the fall, so the fall season is from the beginning of the second week of September to the end of the second week of October. This is a five week period, as it is long enough to find enough data but also is not too long in order to make sure the routes are covered efficiently. Fall migration (for passerines) spans from August to December but in order narrow down a time window to check, this was the time planned out and we continue to run the season during the time time every fall, although in the last couple years I've surveyed throughout most of the year.
The routes both cover nine of the "worst" appearing buildings for bird strikes on both sides of the campus, so the data represents FATAL strikes from 18 buildings on campus. We still gather data from birds that we find alive/stunned on campus, but for the time being we are only using fatal data for most of our analysis at the current time, but that could change in the future depending on what directions we take. Some of the routes include detrimental buildings such as the Beckman Institute, Electrical and Computing Engineering, the Business Instructional Facility, and Temple Hoyne Buell Hall. In the last couple years, we have added two new buildings, the Campus Instructional Facility and the Siebel Center for Design, two buildings that were completed in 2021 and since these buildings are basically solid glass, we figured to include these on our survey. I am very thankful we did as these buildings have proven to be very detrimental for birds. We survey both routes twice a day, once in the early morning to find birds that hit during the night or at first light, and once again in the evening to find birds that strike during the day time. In the morning mostly correlating to birds that strike due to light and evening mostly correlating to birds that strike due to reflectiveness of windows of nearby greenery.
North Quad Route
South Quad Route
Beckman Institute (North Quad)
Business Instructional Facility (South Quad)
Fall 2022 Data:
First I will present data about the birds we found, then compare some results with averages from the last few years. This post is mostly just showing the data we have so far, not necessarily explaining in-depth about the data we have, that maybe for another date. Also, most of this will be only from our main season but I will show some results from outside of the season. We found 77 during the preseason, 133 during our main season, and (so far) 41 during the postseason. Our season average was 3.8 birds found per day.
Tennessee Warbler was by far our most struck species representing 21% of strikes found during the season with 28 individuals. The next five most struck species were Nashville Warbler (10), Ruby-throated Hummingbird (10), Bay-breasted Warbler (8), Magnolia Warbler (7), and Yellow-bellied Sapsucker (6). There were a few interesting birds such as Eastern Wood-Pewee (first ever), Wood Thrush (first ever for fall), Golden-crowned Kinglet (3, first ever IN season, usually found later on), and Blackpoll Warbler (second ever) most of this species does an elliptical migration and goes much more east in the fall.
A graph showing fatal strikes during the season this year. Sorry about the labeling with some bird names are cut off, these are "Ruby-throated Hummingbird, Yellow-bellied Sapsucker, White-throated Sparrow, Chestnut-sided Warbler, Black-throated Green Warbler, and Golden-crowned Kinglet, some bird shave long names!
A Tennessee Warbler
We found 32 different species during the season and 47 species during the fall as a whole. 15 of our 32 species were warblers, 4 were sparrows, and so on. ALL of the species during during the season were migrants, with not a single resident bird found during the season. As a fall combined, 19 species of warblers were found and only two resident species of birds were found during the period (a House Finch and a Northern Cardinal).
Migrants during the season, as mentioned, represented 100% of strikes and represented 99.2% of strikes during the entire fall. More interestingly, most of these migrants were neotropical migrants. I quickly looked into birds that are non-neotropical and compared it to species that are more neotropical migrants. Some of these (non-neotropical) species include sapsucker, kinglets, wrens, and sparrows, species that mostly breed in the boreal forests and winter either here or areas just south, but mostly do not migrate over the Gulf of Mexico or down into Latin America. Neotropical migrants were found by an overwhelming majority, representing 78.5% of strikes (22 species) found during the season and non-neotropical migrants representing 21.5% (9 species). I also classified some species as "near-distance migrants," birds that breed around here, and migrate small distances. My thought is because of breeding around here, some of these species may be more aware of windows like resident birds are (as our data suggests). Only one of these were found during our season (Brown Thrasher) and only 2 others during the fall (Northern Flicker and American Robin).
When we compare what we find based on the families, we find that Parulidae (warblers) are found by far the most, representing 62% of the strikes found, followed by Passerellidae (sparrows). We found birds from 14 different families during the season, and 16 during the entire fall (Fringillidae with the House Finch and a Caprimulgidae with a COMMON NIGHTHAWK)!
This fall had the second lowest strike rate over the four falls, ranging from 110 to 180 strikes over the 18 buildings on campus (not encompassing any Main Quad buildings), with 133 this year, but that is also comparing to years that when CIF and SCD were not surveyed (representing 34 strikes this year). Between last year and this year, we found 44 less strikes. Some of this may be because of a two day mass casualty event last year on 9/22 and 9/23 with a combined 34 fatal strikes between those two days, whereas this year we found several days with 10-15 fatal strikes, but never more than 15. This was because of a mini-fallout coupled with a very thick fog that occured during one day, causing over 35 birds (fatal and non-fatal) found throughout 25 buildings on campus on this day alone.
When comparing to previous years, there were some significant differences with some species as well as some family groups. First, birds that we found much more than our 3 year average (2022:ave) were Ruby-throated Hummingbird (10:4), Tennessee Warbler (28:24), Chestnut-sided Warbler (5:1), Golden-crowned Kinglet (3:0), and White-throated Sparrow (5:3). There were also several species that were found at much lower rates than in the past three years with Swainson's Thrush being the frontrunner with (4:17), then Ovenbird (5:11), Red-eyed Vireo (0:4), Bay-breasted Warbler (8:11), and Black-and-white Warbler (0:3).
The birds that were not found as much as previous years are actually very interesting. This is because all of these species, even species that were not found during the survey, were found during the preseason in large numbers. For example, we found 15 Swainson's Thrushes during the three week preseason when compared to 4 during the whole five week fall season. We also found 7 Black-and-white Warblers, 2 Red-eyed Vireos, and 4 Ovenbirds. This fall, it seemed as if the strike rates were more gradual during the season, roughly having a 40-65 strike rate per week during all weeks during September, whereas last fall we had one very high struck week during the third week of September. Also, noting some species striking (and likely migrating) earlier than usual.
Because of some of these differences, there were also noticeable differences within the family groups. Parulidaes (warblers) were found more often than years prior with (81:73), followed by Trochillidae (Hummingbirds) (10:4) and Passerellidae (sparrows) (13:5). The problem is with sparrows is that our season ends as the sparrow migration starts to ramp up, so most of the birds are found during the postseason, for example Dark-eyed Junco with 12 found during our postseason this fall and none found during the actual season. As mentioned before, our Swainson's Thrush numbers were much lower this fall, which is reflected in the numbers of Turdidaes found with a (8:23) comparison, followed by Cardinalidae (1:4).
Since this post is mostly about the birds themselves, I will briefly show some building data but will not go too in-depth with this at the current time.
In General, we find more birds in the fall than we do in the spring (roughly a 3:1 comparison) and we typically find more birds on the North Quad (roughly a 2:1 comparison). Although, during our postseason, we find many more birds on the South Quad than we do the North (this fall is a 3:1 comparison). We have some ideas on why this could be occurring, but will wait until another time to explain this. One could be because some of the buildings on the south side are more single story orientated (in general all of the buildings on the NQ have window faces at least two stories or higher), whereas on the south quad we survey four buildings that are or nearly a single-story window (Siebel Center for Design, Krannert, Law, and Education Buildings and lower (later) birds may strike these buildings more often, but we are still looking into this.
The new Siebel Center for Design showing the "one-story" window face
The highest struck buildings during the season were Beckman (33), Campus Instructional Facility (23), Electrical & Computing Engineering (16), Business Instructional Facility (13), and Siebel Center for Design (8). Unlike prior years, Beckman was not as strong as an outlier as the past which is something to watch, as nothing of what I found from the building or the glass had changed over the years. Although there was loud construction from the west end of the nearby Coordinated Science Laboratory starting at 7am most mornings during at least half of the season so this definitely could be a constraint and a reason why we did not find as many here as the year prior (with 57 strikes) and also why we ended up behind in number of total strikes for the season when compared to last year. It is also important to note that the two newly constructed buildings (CIF and SCD) made it on the most struck list during the season.
The "new" Campus Instructional Facility
For now this will be all about the project. This was just to present our data for this current fall as I have never done so before, but not going too much into discussion about our findings. I will be doing plenty of things during the offseason so some progress will be coming soon! Thanks for reading and stay tuned!