COURTSHIP DISPLAYS AND SONATIONS OF A HYBRID MALE BROAD-TAILED x BLACK-CHINNED HUMMINGBIRD

We describe the courtship displays and sonations of a male hybrid Broad-tailed x Black-chinned Hummingbird (Selasphorus platycercus x Archilochus alexandri). The hybrid performed shuttle and dive displays similar to the displays of the parent species. His wing and tail morphology were intermediate between those of the parental species. The hybrid produced dive sounds with rectrix 5 (R5), matching the mechanism of the tail-generated portion of the dive sound of the Black-chinned Hummingbird, and not matching that of the Broad-tailed Hummingbird, which uses rectrix 2 (R2). The hybrid's R2 was capable of fluttering at a frequency and mode similar to those of the Broad-tailed's R2, but unlike the Broad-tailed's R2, the hybrid's R2 produced little sound. During displays, but not during ordinary flight, the hybrid's wing trill was higher pitched than that of either parental species. These results indicate that small changes in feather morphology can result in comparatively large changes in sound production. All of the hybrid's morphological characters and most of the display characters were intermediate between those of the parental species; at least one behavioral character was transgressive, suggesting that some behavioral display characters may be under the control of comparatively few genes.