Meeting Abstract
Hybrid zones have received significant attention in biology, but few studies have investigated how behavioral traits vary across these regions of interaction. In a hybrid zone in southern Oregon and northern California between the Allen’s (Selasphorus sasin) and Rufous (Selasphorus rufus) Hummingbirds, we found that hybrids vary in morphology and behavior. We describe the hybrid zone by characterizing variation in phenotype across the area of contact and study a novel courtship behavior in Allen’s Hummingbird, the pendulum display. The courtship displays of both species involve a male hummingbird performing a J-shaped dive, during which the male produces a species-specific sound with his tail feathers. These displays can be broken into distinct elements, and some dive elements are analogous to those in the pendulum display. Hybrids perform courtship displays that incorporate different elements of the displays of parental species. Our data suggest the center of the hybrid zone spans from Bandon, Oregon, to Port Orford, Oregon, and spans several miles inland and north into the range of Rufous Hummingbird (as far north as Florence, Oregon), and south into the range of Allen’s Hummingbird (as far south as Arcata, CA). Additionally, we find the breaks across the hybrid zone (pure Allen’s to Allen’s-like hybrid range, Allen’s-like hybrid to the center, center to Rufous-like, Rufous-like to pure Rufous) correlate with variation in temperature and rainfall data, consistent with previous findings that suggest Rufous Hummingbird is dependent on habitat with cool forests with high rainfall. Few studies have incorporated analysis of the variation of behavior across an area of contact. By doing so, we add an additional, understudied layer of biology to the study of hybrid interactions.
