As you observe migrating hummers, you'll notice that they do not travel in flocks. As solo fliers, they are harder to spot by predators. When the tiny birds stop to refuel, they don't have to find food sources abundant enough to feed a large group. Overall, the habitat needs of a migrant are more easily met by flying solo.
"Salvia Amistad is a favorite in the garden right now."
Linda Tully P. Highland, Maryland 08/24/15
Linda Tully P.