Long Point Bird Observatory, situated on a 40-kilometre sandspit near Lake Erie in southwestern Ontario, is a UNESCO Biosphere Reserve and the oldest continuously operating bird sanctuary in North America. However, recent research from the Proceedings of the National Academy of Sciences indicates that the effects of climate change are disrupting the ecosystem of this protected area.
The study, conducted by researchers from the University of Michigan and Birds Canada using historical data from Long Point Bird Observatory, reveals concerning trends among tree swallows. Since 1969, tree swallows at Long Point have been laying fewer eggs and experiencing a reduction in body size. Additionally, the study notes a significant decline in aerial insectivores, including tree swallows, by 43%, along with a more than 60% decrease in the insect population since 1977.
Lead author Charlotte Probst, a PhD student at the University of Michigan, highlighted the importance of tree swallows as a model species for research due to their nesting behavior. The study points out a phenological mismatch caused by climate change, where insects are emerging earlier while the timing of bird migration and breeding remains unchanged, leading to decreased food availability for the swallows.
Research ecologist Matthew Fuirst, a co-author of the study, emphasized the impact of low insect abundance on the health and reproduction of tree swallows. The study found that the mismatch in timing between swallows and insects has been increasing by more than three days per decade since 1977, resulting in smaller body sizes and reduced egg production among the birds.
In addition to the timing mismatch, declining insect populations, as observed by PhD candidate Hadil Elsayed from York University, are exacerbating the challenges faced by tree swallows. Elsayed’s research indicates that insect emergence is occurring earlier due to rising temperatures, causing a disruption in the food chain for the swallows.
Probst, Fuirst, and Elsayed suggest local actions to mitigate the impact of insect declines, such as planting native wildflowers, reducing pesticide use, and preserving habitats for insects. By addressing these local issues, the researchers believe it is possible to support the ecosystem at Long Point Bird Observatory and help tree swallows thrive in the face of climate change challenges.