LVSteve
Member
Many times when people are telling me about seeing hummers, I hear, "It had a black head", and "It changed color". While there are hummers with black heads, some times what the observer is seeing is one of the effects of iridescence on the feathers. As the light catches the fine structure of certain feathers, the color you observe changes. Below is a male Anna's Hummingbird demonstrating the effect.
Enjoy!
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Enjoy!

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