Figure 1.

Tail morphology and manipulations of tail length in Anna's hummingbirds: (a) the arrow indicates where two feathers have been spliced together (see text for more details), (b) rectrices and (c) tail coverts; (d–h) five consecutive experimental manipulations: (d) no manipulation (control 1), (e) long-tail treatment, (f) sham manipulation (control 2), (g) no-rectrices treatment and (h) no-tail treatment (rectrices and coverts removed); and (i) photo of a male Anna's hummingbird flying with attached tail streamers.