Maximum Entropy Modeling Loggerhead Shrike Distribution in Southern Ontario

The Loggerhead Shrike is a critically endangered species in Ontario[1] and with climate change increasingly threatening avian habitats[2], it is expected to become even more endangered in the years to come. Additionally, the habitat of the Loggerhead Shrike is not comprehensively understood[3] which makes it an interesting subject of study. Across Ontario, the Loggerhead Shrike is found notably in two distinct pockets: one is around Napanee, and the other is just Northeast of Lake Simcoe, an area at risk of development. This study focuses on the second area and aims to leverage distribution modeling technology in the hopes of a) identifying suitable areas for the Loggerhead Shrike and b) creating a clearer picture of the bird’s ideal habitat. Given a lack of species absence data, a Presence-Only Prediction (MaxEnt) model is used within ArcGIS Pro to create a prediction surface based on input presence points from iNaturalist. Extensive research was done to choose a set of environmental variables[4] (e.g., land cover, elevation, NDVI, etc.) to be tested for significance in the model. The preliminary outputs of the model are then tested for accuracy through both an automated (resampling) and custom validation method. The latter is done by plotting the observed points against their model-predicted presence values and comparing that to an ideal scenario, in which the model’s success at identifying suitable habitats is quantitatively estimated and subsequently re-tested with different parameters and variables. Preliminary results show that low elevations, grasslands, and significant distance from roads are key habitat-determining elements. There is potential for this approach to be used in conservation efforts for nesting birds more generally. [1] Government of Ontario. (2007). Endangered Species Act, 2007, S.O. 2007, c. 6. [2] Trautmann, S. (2018). Climate change impacts on bird species. Bird Species: How they arise, modify and vanish, 217-234. |[3] Chabot, A. A., Titman, R. D., & Bird, D. M. (2001). Habitat use by loggerhead shrikes in Ontario and Quebec. Canadian Journal of Zoology, 79(5), 916-925. [4] Government of Canada; Government of Ontario; U.S. Geological Survey