Description wikipedia

The green warbler-finch (Certhidea olivacea) is a species of bird, one of Darwin's finches in the tanager family Thraupidae. Sometimes classified in the family Emberizidae, more recent studies have shown it to belong in the tanager family. When Darwin collected it in 1835 during the Beagle survey expedition he mistakenly thought it was a wren, but on return to England he was informed in March 1837 by the ornithologist John Gould that the bird was in the group of finches. It is endemic to the Galápagos Islands, Ecuador. This species is closely related to the grey warbler-finch, and the two were formerly considered conspecific, but both species differ in appearance, distribution, habitat, and song. Holding a distinctive place in the evolutionary history of Galápagos finches, phylogenetic studies suggest that the warbler-finches represent one of the earliest branches in the radiation of Galápagos finches, diverging prior to the more well-known ground finches and tree finches. With its slender, pointed beak adapted for capturing insects, the green warbler-finch occupies a unique ecological niche within the Galápagos archipelago. As such, the green warbler-finch serves as a crucial species for understanding the evolutionary processes that have shaped the remarkable avian diversity found in this iconic ecosystem.