Puffins on Machias Seal Island share their habitat with several other seabird species, including razorbills, common murres, and Arctic terns. This creates a lively and competitive ecosystem, particularly during the breeding season. The puffins here often have to navigate around aggressive Arctic terns, which are fiercely protective of their nests. Despite this, the puffins thrive on the island's rocky terrain, which provides ideal conditions for their burrows and a steady supply of fish from the surrounding nutrient-rich waters. This coexistence makes Machias Seal Island a vital and vibrant sanctuary for seabird biodiversity in the Gulf of Maine.