This post was contributed by Ethan Gyllenhaal, co-author of a paper in a recent issue of the The Wilson Journal of Ornithology documenting the unusual warbler hybrid described here.
Before I started down the academic path of ornithology, I was a birder with an appetite for difficult bird IDs. I loved the challenge of identifying the gulls that wintered along the shores of Lake Michigan, where I grew up. With so much variation within gull species and such subtle differences between species, each individual was a new puzzle. One complication is that many species of gull regularly mate with each other, producing intermediate hybrids. The strict definition of a species I learned in high school, which said different species never interbred, was clearly an oversimplification. I regularly saw rarer hybrids between distinct species (e.g., Herring x Great Black-backed Gull) and challenging individuals that were the products of hybrids swarms (i.e., Iceland Gulls). My fascination with the complexity of this phenomenon led to my desire to track down hybrids I’d never seen before, as I would any other new life bird.
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