Allen’s Hummingbird: ID, Range and a Species Divided

Allen’s Hummingbird is one of the most threatened hummingbirds in North America. It is also one that has colonised a major city within living memory.
Hummingbirds in California: Species, Seasons, and Gardening

Anna’s Hummingbird lives here all year and does not leave. Costa’s stays put in parts of the south. And Allen’s Hummingbird has split into two populations: one that still flies to Mexico each winter, and one that has stopped bothering and now breeds in Los Angeles gardens twelve months a year. In a state with a Mediterranean climate, mild winters, and gardens that flower in January, the ancient pressure to fly south has eased considerably.
Types of Hummingbirds: A Field Guide to North American Species

Somewhere between 300 and 360 species of hummingbird live in the Americas, but you do not need to know all of them to identify the one hovering at your feeder. North of Mexico the list is far shorter and very learnable.
Hummingbird Sounds, Chirps & Territorial Behavior Explained

Do hummingbirds chirp? Yes, and they also sing, whistle, and chirp with their tail feathers. Discover what every hummingbird sound means and why they make it.

