Migration Info This west coast hummingbird is such an early migrant that the typical terminology we apply to the timing of migration is hardly appropriate. Male Allen's Hummingbirds may begin to leave their winter range in central Mexico in late autumn, and some leave their west coast breeding areas to return southward as early as late spring. In the southern part of their breeding range, along the southern California coast, males can be found defending territories as early as the first week of January. What these tiny hummingbirds lack in size, they make up for in pugnacity; the first sign that the Allen's Hummers are back on breeding territories in February is when they chase the larger, resident Anna's Hummingbirds away from their favorite flowers and feeders. Nonmigratory populations in southern California feed heavily on eucalyptus and other non-native ornamentals, which may mean that their nonmigratory behavior is a result of human-caused changes.