Scientists Identify Previously Unknown "Hybrid Zone" Among Hummingbird Species

We generally think that a species is reproductively isolated, that is, it does not breed with other species in the wild. Sometimes, however, closely related species cross each other. New search has just appeared in Auk: Ornithological progress documents the existence of a hybrid zone not yet discovered along the coasts of northern California and southern Oregon, where two closely related hummingbirds, Allen's Hummingbird and Rufous Hummingbird, are fuzzy areas. The researchers hope that the case study like this one could improve their understanding of creating and maintaining biodiversity.

A hybrid zone is an area where the ranges of two closely related species overlap and intersect. To map the extent of the Hybrid Hummingbird Zone of northern California and southern Oregon, Brian Myers of the State University of San Diego and his colleagues collected data on the physical characteristics and yard behavior of more than 300 hummingbirds in the region. Most of the breeding males in the hybrid zone had a mixture of characteristics of both species, moving gradually from north to north to Rufous-type birds and further south to Allen-type birds.

Males of different species of hummingbirds have distinct presentations, performing aerial acrobatics in which their tail feathers produce various sounds. The researchers captured hummingbirds using traps near the feeders, temporarily keeping the females in wire cages, where they attracted the attention of the territory's men. "Sometimes the birds outperform me," says Myers. "They will only visit a feeder when the trap will not be there, or they will not show up in front of the female hummingbird that I carry, and that can sometimes slow things down."

The area where the Allen and Rufous hummingbirds cross extends over 300 km along the Pacific coast and 90 km inland, which could have consequences for the region. the future of the species. "When a hybrid zone is as large and one of the hybridizing species has a distribution area as small as Allen's Hummingbird, it is possible that their range will further shrink at the genes." Allen's hummingbird populations, "says Myers. "As biodiversity continues to decline, it is more important than ever to understand how new species are formed and what keeps species barriers once they are created – is there a habitat or other resources that need protection? Is it more related to sexual selection? Hybrid zones are an ideal tool for studying this. "