As areas become more urbanized, fauna are continually exposed to novel anthropogenic structures and are forced to adapt. However, adapting is not always an option. For example, we see that individuals across various groups have not adapted to roads and train tracks (e.g., deer, bears, birds) and the outcome is fatal. Instead of creating barriers to these areas to prevent organisms from interacting with these urban areas, leading to possible reproductive isolation, the solution here is to develop a way to effectively alert individuals as they approach these areas.
If we focus on avian systems, we see that windmills, skyscrapers, and aircraft pose a threat to avian fauna due to their flying mechanisms. In window collisions alone, roughly 1 million birds die per year, showing that colliding with structures is one of the leading causes of mortality in birds. Birds have better lateral vision than binocular vision when flying and are often looking down to observe the landscape and search for resources (e.g., food, water, roosting grounds). Additionally, birds can act as pests to farmers, destroying crops, and can damage buildings/structures when colliding with them. Current technology is not working against these issues but instead, habituating birds to startles (e.g, propane cannons) or harming the environment (e.g., avicide). It is clear that these methods are ineffective and that there is a need to solve this persisting issue. This is crucial as birds are often viewed as the “heartbeat” of an ecosystem and can serve as indicators of environmental change. If we remove these birds from their systems, or their numbers drop drastically, we will see the entire area change dramatically. So, how do we successfully deter birds from particular areas and prevent them from causing damage?
Variation in the visual fields of birds compared to humans (Martin, 2009).
Timothy Boycott, who recently completed his MS at the College of William and Mary in the Swaddle Lab, presented his work on how to use aspects of behavioral and sensory ecology to prevent avian collisions with particular man-made structures. Building off previous work from the Swaddle Lab (Swaddle and Ingrassia, 2017) in a captive setting, Boycott and Swaddle aimed to translate these findings into an outdoor setting, characterize elements of effective acoustic signals, and develop a behavioral analysis for collision risk. Using two acoustic signals, 4-6 kHz and 6-8kHz, they set up directional sound fields at communication tower sights and video cameras. They recorded the behavior of birds without sound to produce 3-D models of their flight patterns and compared these two the two treatments using sound to deter birds. They found that bird activity was lowest around the tower during 4-6 kHz conditions, but there were no significant differences. Although there no significant differences in the flight-change distance and change in angle displacement between groups, we see that birds exposed to the treatments stayed further from the tower, and those exposed to the 6-8 kHz had a larger angle displacement. Despite the non-significant difference in angle displacement within a flight, there were significant differences between the control and both treatments in the overall displacement angle.
Boycott and Swaddle showed that 4-6 kHz frequencies were most associated with a reduction in overall bird activity, slower velocities, greater distance from towers, and tower displacement angles. 6-8 kHz were less associated with these and more associated with within-flight measures, pushing them to suspect that this frequency may be less detectable to birds or that the effect is delayed. Boycott and Swaddle are suggesting that moving forward, researchers should be encouraged to use behavioral data when measuring collision risk. Overall, this research provided a viable solution for solving the crisis birds are facing in the Anthropocene.
Check out Timothy Boycott to see more of his work and check out the Swaddle Lab for more human-wildlife conflicts surrounding avian systems.
Featured Imag: “What Drives Bird Vision” Bill Control and Predator Detection Overshadow Flight” by Graham R. Martin
- Social-Ecological Frameworks and What the Future May Hold - May 26, 2022
- What’s Missing in Urban Ecology? - May 10, 2022
- Urban Wildlife Spotlight: The Monk Parakeet - September 2, 2021
Leave a Reply