Scarlet-rumped Tanager (female) and Golden-hooded Tanager, Las Cruces Biological Research Station, San Vito, Costa Rica, December 2021 — I mentioned that the Passerini’s and Cherrie’s Tanagers were considered separate species, each with an isolated range on either cost of Costa Rica (no overlaps)…at least for a while. They were once considered the same species, named Scarlet-rumped Tanager…and then the AOU (the bird naming committee) decided they were different, based on range, and on the obvious differences in the plumage of the females (the males are identical), but recently ornithologist have come up with a new method to study species, called the “playback method”. They play recorded songs and calls of an apparently closely related species, to determine if the birds under study respond as they do to their own calls and songs. In the case of Passerini’s and Cherrie’s Tanagers, both respond equally as well to the other’s songs and calls…making it very likely that they are the same species, or at least that they would interbreed if their ranges overlapped. This inspired genetic studies to follow up…and indeed they appear to be the same species, just separated by a mountain range. The Golden-hooded Tanager just had to get into the photo. Sony Rx10iv at 591mm equivalent. Program mode with wildlife modifications and multi-frame noise reduction. Processed in Pixelmator Photo and Apple Photos. Equivalent ISO 2500 @ f4 @ 1/500th.