puffleg (PUF-leg) - n., any of numerous species of hummingbirds of the genera Eriocnemis and Haplophaedia, with large tufts of downy feathers on the legs.

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There are somewhat more than a dozen species, with a couple under debate over whether subspecies or their own thing. The above picture is a sapphire-vented puffleg (Eriocnemis luciani), of whom the photographer
notes, "Now there's one undertail that's amazing to look at! ^_^ " The name is, well, you know.
---L.

Thanks, WikiMedia!
There are somewhat more than a dozen species, with a couple under debate over whether subspecies or their own thing. The above picture is a sapphire-vented puffleg (Eriocnemis luciani), of whom the photographer
notes, "Now there's one undertail that's amazing to look at! ^_^ " The name is, well, you know.
---L.