[birding] Female Anna's Hummingbird singing?

[Lisa Millbank]

Has anyone ever heard a female Anna's Hummingbird sing, or seen one perform a display flight (omitting the loud "shink!" sound the male produces at the bottom of the dive)?
At the community garden at Starker Park, this feisty female-plumaged Anna's (click to see photo) has been singing a lot, chasing other hummingbirds away, and rising vertically until she almost disappears, then zooming down repeatedly in a series of U-shaped dives.  Is it possible "she" is actually an immature male, already showing some behaviors of adult males while keeping his juvenile plumage?  Or does anyone know if female Anna's Hummingbirds typically do these things?
She is especially fond of the nectar of onion blossoms...if you grow onions, it might be worth leaving some to flower for the hummingbirds.  She also likes to drink water from sprinklers.

Lisa
www.neighborhood-naturalist.com
 

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