The map above showcases (in blue) the states and territories of North America where the Masked Birch Caterpillar may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.*NOTE: States/Territories shown above are a general indicator of areas inhabited by the Masked Birch Caterpillar. Insects generally go where they please, typically driven by diet, environmental changes, and / or mating habits.