Woodpeckers drumming their beaks in trees use the same part of the brain as songbirds learning to sing a tune, according to a new study.
The bird’s forebrain contains specialized pecking regions that resemble those associated with bird song and human language systems.
These have previously only been found in bird species that learn and produce vocalizations, which the woodpecker does not.
However, researchers at Brown University in the United States have found that these same regions are activated by the bird’s characteristic drumming.
The finding suggests that its ability to peck rhythmically evolved in the same way as vocal learning in animals and language in humans.
The downy woodpecker’s forebrain contains specialized pecking regions that resemble those associated with bird song and human speech systems (stock image)
Brain diagrams showing drum control nuclei and their connections in woodpeckers compared to similar nuclei and connections in voice-learning birds. A: The song learning nuclei are RA, HVC, LMAN and area X. B: The drum control 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 non-voice-learning bird species
HOW WAS THE STUDY CONDUCTED?
Scientists knew that some birds learn to vocalize by mimicking older birds, while some are born with this ability.
To check for differences in brain activity between learners and non-learners, they visualized the brains of species in the latter group, including Downy Woodpecker.
To their surprise, the woodpecker showed activity in areas of the brain used by birds learning to sing.
After playing the spikes with drum sounds, the researchers found that it activated these regions of the brain.
This suggests that birds might learn drum patterns from their pecks, rather than vocalizations.
The brain regions they use while pecking may also have evolved similarly to those used for vocal learning by other species.
Lead author Professor Matthew Fuxjager said: “Woodpeckers have a set of specialized brain areas that control their ability to drum or hammer their beaks rapidly on trees and gutters when fighting with other birds.
“Additionally, these brain areas look remarkably similar to the parts of songbird brains that help these animals learn to sing.”
Woodpeckers bore holes in the bark of trees in order to dig cavities to nest and catch food with their long tongues.
They perch vertically on trees and repeatedly click their beaks into the trunks, as if drumming or piercing.
Birds also use noise to defend their territories and scare away potential intruders, similar to birdsong.
The production of drums and bird songs 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) that controls vocalization learning.
PV is also associated with language learning in humans, which is similar to birdsong in that it is learned during youth and requires complex muscle coordination.
However, the gene has never been found in the forebrain of birds that do not learn their vocalizations.
Microscope images of PV-rich forebrain nuclei in a song-learning hummingbird (green box) and a drummer woodpecker (red box). The white dotted regions indicate the boundaries of the song control regions. Blue dashed regions indicate specialized PV regions. Scale bar = 2 mm
Some birds, like hawks, are born with the innate ability to vocalize, while others, like songbirds and parrots, must listen and imitate older birds to learn how to do so.
For this study, published yesterday in PLOS Biologyscientists were testing whether the brains of birds that didn’t learn their calls differed from those that did.
Previous research has suggested that PV activity is stimulated in birds that learn their vocalizations, so they wanted to confirm that this was not the case in some non-learning species.
This included flamingos, ducks, hawks, penguins and the downy woodpecker, but, to their surprise, they found that the latter had specialized brain regions that manufacture PV.
These areas are similar in number and location to several of the forebrain regions that control song learning and song production in songbirds.
Woodpecker drumming, like birdsong, may be a learned behavior and has evolved in the same way as vocal learning in animals and language in humans (stock image)
To test how the downy woodpecker used this part of its brain, the researchers played drum sounds through loudspeakers near their nesting cavities in the wild.
They then examined the woodpeckers’ forebrains that drummed in response to sound and found that this triggered activity in PV brain regions.
This suggests that drumming, like birdsong, may be a learned behavior and evolved similarly to vocal learning in animals and language in humans.
These findings improve understanding of how brain systems evolve to perform new, but similar functions.
Woodpecker heads ‘act like stiff hammers,’ not hard hats, study finds
Scientists have debunked a popular theory that the woodpecker can repeatedly slam its beak against a tree at high speed without injuring its brain.
The researchers analyzed high-speed video of three species of woodpeckers – the pileated woodpecker, the black woodpecker and the great spotted woodpecker.
They discovered that their skulls did not act like shock-absorbing helmets as previously thought, but rather like rigid metal hammers.
In fact, their calculations show that any shock absorption would hamper the pecking abilities of the woodpeckers.