How snowy owl migration could be influenced by climate change, and development along coastal Maine

Background/Question/Methods   The Snowy Owl (Nyctea scandiaca) has been reported as a winter visitor to the Northeastern United States since the pre-Colonial period. Previous sightings of owls in coastal Maine suggest that they primarily use off-shore islands, fields and mountaintops (> 400 m) as wintering sites. Acadia National Park, Mount Desert Island, Maine, considers snowy owls a significant biological resource, and there is concern that changes in climate and wind turbines may influence owl, and other bird, migration. I identified areas on Mount Desert Island and surrounding islands where there have been high numbers of owl sightings in the past. I then compared the areas' vegetation density and elevation to examine the relationship between owl sightings and preferred habitats. Prior research suggests that snowy owl migration and winter dispersal correlates with weather. I therefore also compared years with an abnormally large number of owl sightings along the Maine Coast with regional weather patterns. I discuss how climate change and development, specifically wind turbines, could influence owl migration and habitats in the future and the implications of these changes on Acadia National Park.

Results/Conclusions   Research suggests that snowy owls migrate south in higher numbers when there is a colder winter, and less prey availability up north. The owls' migration patterns may also follow a cyclical population fluctuation of their primary prey, the lemming. Owls prefer sites on the Maine Coast that have a significant amount of open space, including bare rock and/or short (< 1m.) vegetation. These conditions are common on high ridge tops and also on many off-shore islands. Unfortunately, this has the potential to draw owls into areas that are favored for wind-turbine development in both terrestrial and mid-water habitats.