The “triple hybrid’s” ancestry chart, courtesy of the Cornell Lab of Ornithology.

A remarkable “new bird” was discovered and photographed in Pennsylvania by an avid birder, Lowell Burket. The hybrid bird is extremely rare, and its genetics are complicated! To produce this apparent hybrid of three warbler species, the adult female that raised the new hybrid was itself a hybrid between a Golden-winged Warbler and Blue-winged Warbler, which is a very rare hybrid in itself, known as a “Brewster's Warbler.” That female “Brewster’s Warbler” hybrid mated with a male Chestnut-sided Warbler and successfully laid at least one fertile egg and raised the nestling to fledging, and it survived. The offspring could be called a three-way hybrid with an ancestry of three different species of warblers.

Hybrid birds are vey rare, but “triple hybrids” are virtually unheard of. In this case, it’s a matter of a hybrid female hybridizing with a male from another species. Are you keeping all this straight? It’s all very interesting, very exciting for ornithologists, geneticists, the general public and, of course, birders.

To read one of many articles written recently about this extraordinary hybrid warbler, see https://www.sciencealert.com/this-tiny-birb-is-three-different-species-in-one-adorable-package