Vocal learning is thought to have evolved in three orders of birds (songbirds, parrots, and hummingbirds), with each showing similar brain regions that have comparable gene expression specializations relative to the surrounding forebrain motor circuitry. Here, Schuppe et al. searched for signatures of these same gene expression specializations in previously uncharacterized brains of seven assumed vocal non-learning bird lineages across the early branches of the avian family tree. These findings revealed little evidence of such specializations in these taxa, except for woodpeckers, which possess forebrain regions that are anatomically similar to the pallial song nuclei of vocal learning birds. Field studies of free-living downy woodpeckers revealed that these brain nuclei show increased expression of immediate early genes when males produce their iconic drum displays, the elaborate bill-hammering behavior that individuals use to compete for territories, much like birdsong. Other woodpecker species also contain these brain nuclei, suggesting that these brain regions are a common feature of the woodpecker brain. The image shows a free-living adult male downy woodpecker (Dryobates pubescens).

Image Credit: mjeedelbr, Flickr