Woodpeckers drumming on trees use the same part of the brain as songbirds learning a tune
Woodpeckers drumming their beaks into trees are using the same part of the brain as songbirds learning to sing a tune, a new study has found.
The bird’s forebrain contains specialised pecking regions that resemble those associated with birdsong and human language systems.
These have previously only been found in bird species that learn and produce vocalisations, which the woodpecker does not.
However, researchers at Brown University in the USA found these same regions are activated by the bird’s characteristic tree drumming.
The finding suggests that its ability to rhythmically peck has evolved in the same way as vocal learning in animals and language in humans.
The downy woodpecker’s forebrain contains specialised pecking regions that resemble those associated with birdsong and human language systems (stock image)
Brain diagrams showing drum control nuclei and their connections in woodpeckers compared to similar nuclei and connections in vocal learning birds. A: Song learning nuclei are RA, HVC, LMAN and Area X. B: Drum controlling nuclei are arcopallium (dA), anterior nidopallium (dAN), and dorsal lateral nidopallium (DLN). C: No nuclei are present for song learning and woodpecker drumming in the brains of vocal non-learning bird species
Lead author Professor Matthew Fuxjager said: ‘Woodpeckers have a set of specialised brain areas that control their ability to drum, or rapidly hammer their bill on trees, and gutters, during fights with other birds.
‘Furthermore, these brain areas look remarkably similar to the parts of the brain in songbirds that help these animals learn to sing.’
Woodpeckers bore holes into the bark of trees in order to carve out cavities for nesting and catching food with their long tongues.
They perch vertically on trees and slam their beaks repeatedly into the trunks, as if drumming or drilling.
The birds also use the noise to defend their territories and scare off potential intruders, in a similar way to birdsong.
Both drumming and birdsong production also requires rapid and complex motor movements, and must be adaptable when birds compete with each other.
These factors suggest they may have neurological similarities, and songbirds are known to express a marker gene called parvalbumin (PV) which controls vocalisation learning.
PV is also associated with language learning in humans, which is similar to birdsong in that it is learned while young and requires complex muscle coordination.
However, the gene has never been found in the forebrain of birds that do not learn their vocalisations.
Microscope images of PV-rich forebrain nuclei in a song-learning hummingbird (green box) and drumming woodpecker (red box). White dashed regions indicate boundaries for song control regions. Blue dashed regions indicate specialised PV regions. Scale bar = 2 mm
Some birds, like hawks, are born with the innate ability to vocalise, while others, like songbirds and parrots, must listen to and mimic older birds to learn how to do it.
For this study, published yesterday in PLOS Biology, scientists were checking to see if the brains of birds that do not learn their calls look different to those that do.
Prior research has suggested that PV activity is boosted in birds that learn their vocalisations, so they wanted to confirm that this was not the case in certain non-learning species.
This included flamingos, ducks, hawks, penguins and the downy woodpecker, but, to their surprise, they found the latter did have specialised regions of the brain that make PV.
These areas are similar in number and location to several of the forebrain regions that control song learning and production in songbirds.
Woodpecker drumming, like birdsong, could be a learned behaviour, and has evolved in the same way as vocal learning in animals and language in humans (stock image)
To test how the downy woodpecker utilised that section of its brain, the researchers played drumming sounds through speakers near their nesting cavities in the wild.
They then examined the forebrains of the woodpeckers that drummed in response to the sound, and found that it triggered activity in the PV brain regions.
This suggests that drumming, like birdsong, could be a learned behaviour, and has evolved in the same way as vocal learning in animals and language in humans.
These findings increase understanding of how brain systems evolve to perform new, but similar, functions.