Baby Hummingbirds In The Nest

The Rufous hummingbird is one of several species that breed in temperate western North America and winter in increasing numbers in the warm subtropical southeastern United States, rather than in tropical Mexico. By migrating in Spring as far north as the Yukon or southern Alaska, the Rufous hummingbird nests farther north than any other hummingbird species and must tolerate occasional temperatures below freezing in its breeding territory. This cold hardiness enables it to survive temperatures below freezing, provided that adequate shelter and food are available.
The northward migration of Rufous hummingbirds occurs along the Pacific flyway and may be time-coordinated with flower and tree leaf emergence in Spring in early March, and also with availability of insects as food. Arrival at breeding grounds before nectar availability from mature flowers may jeopardize breeding opportunities, a factor of phenology possibly determining future migratory patterns linked to climate change.
• Superficially similar birds
Some species of sunbirds of Africa, southern and southeastern Asia, and Australia resemble hummingbirds in appearance and behavior, as do perhaps also the honeyeaters of Australia and Pacific islands. These two groups, however, are not related to hummingbirds, as their resemblance is due to convergent evolution.