Spring hummingbird migration begins as early as January and fall migration begins as early as July. Most hummingbirds, however, begin moving north in May and south in August.
There are over 300 species of hummingbirds but only a few of these migrate. In North America, migratory hummingbird species move between a summer breeding range in the north and a more southerly winter range. Hummingbirds migrate individually, rather than in flocks like many other bird species, and individual hummingbirds often develop a predictable migratory pattern. The earliest migrating birds leave their wintering grounds in January and move south again beginning in July. Most hummingbirds begin arriving in their breeding range by the middle of May, and the peak of fall migration is typically the middle of August or early September.
Hummingbirds migrate based upon factors such as food availability, age and sex. Males and older birds tend to begin migrating earlier than females and juveniles. It is a common myth that leaving backyard hummingbird feeders out too long prevents birds from migrating. While food availability does play a role in migration, hummingbirds do not delay migration if a feeder is available. In fact, leaving feeders out late into the fall is an excellent way to help late migrators find enough food to continue on their journey.