Cryptic species? Wilson's Warbler...
"Look up Wilson’s Warbler in your favorite field guide, and you’ll find a single species, but more and more research suggests that it’s just a matter of time until you see two....nuclear and mitochondrial DNA analysis performed in 2011 revealed strong differences between the eastern subspecies and its two western counterparts but only subtle differences between the western pair. The genetics led the researchers to suggest that the two groups were cryptic species — that is, distinct species that have been hidden, erroneously, under one species name."birdwatchingdaily.com
Cryptic species? Wilson's Warbler...
"Look up Wilson’s Warbler in your favorite field guide, and you’ll find a single species, but more and more research suggests that it’s just a matter of time until you see two....nuclear and mitochondrial DNA analysis performed in 2011 revealed strong differences between the eastern subspecies and its two western counterparts but only subtle differences between the western pair. The genetics led the researchers to suggest that the two groups were cryptic species — that is, distinct species that have been hidden, erroneously, under one species name."birdwatchingdaily.com