Is there a sentence fragment?
Due to warmer winters, the population of brown tawny owls in Finland has increased dramatically. With less snow on the ground, brown owls can better blend in with the environment, evading predators.

 - no
 - yes
There is not a sentence fragment. These are complete sentences because they express complete thoughts.
Due to warmer winters, the population of brown tawny owls in Finland has increased dramatically. With less snow on the ground, brown owls can better blend in with the environment, evading predators.