There are two eagles that make their nest each year on an island that is about 1000' from my shore line. Another very important reason to maintain VLOS ... other than to check for seaplanes and ultralight (which frequent my lake) is to keep an eye on eagles. The best evasive measure, if they approach your drone is to fly straight up rapidly. Birds attack from above. Your drone flies upward rapidly and downward slowly. Trying to fly horizontally with evasive maneuvers won't work either.