A new study led by Francis Quang-Hai Dinh at McGill University delved into the population of grey and black squirrels across various parks in the Montreal area. Dinh, using his bicycle to navigate suburban areas due to limited transportation options, meticulously observed and documented over 800 squirrels in nearly 200 green spaces.
The research revealed interesting findings about the distribution of black squirrels in Montreal. Dinh noted that as he moved further north, the prevalence of black squirrels increased significantly. In regions just north of Laval, up to 40% of squirrels were black, while on the island of Laval, the percentage was around 20%. Comparatively, on the island of Montreal, approximately 15% of squirrels were black, and on the south shore, the number dropped to just two or three percent.
The study attributed this phenomenon to temperature variations, with cooler climates in northern areas favoring black squirrels due to their better heat absorption capabilities. Additionally, the density of forest cover played a role, as black squirrels blend in more effectively in areas with a darker backdrop.
The senior author of the study, Allison Roth, emphasized that the research aimed to use squirrels as a model to understand how urban environments influence evolutionary changes. Montreal’s unique layout, segmented by waterways like the St. Lawrence River, creates diverse environmental conditions that lead to genetic and physical adaptations in the squirrel population.
Unlike previous studies comparing urban and rural wildlife, this research focused on fine-scale variations within neighborhoods. It highlighted that urbanization indirectly impacts squirrel melanism through factors like vegetation structure and microclimates, rather than being a direct predictor.
The study, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” is part of a special feature by ecology journals exploring collaborative approaches to ecological research. Dinh, reflecting on the study’s implications, emphasized the coexistence of wildlife and urban development, challenging the notion of nature and the city as separate entities.