Song sparrows shuffle and repeat to keep their audience listening
Playlist is switched up and remembered for at least 30 minutes
Date:
January 26, 2022
Source:
Duke University
Summary:
Biologists have found an animal for the first time that communicates
with the complexity of human language: song sparrows. According to
a new study, male song sparrows memorize a 30-minute long playlist
of their recently belted tunes and use that information to curate
both their current playlist and the next one. The findings suggest
that song sparrows deliberately shuffle and repeat their songs
possibly to keep a female's attention.
FULL STORY ==========================================================================
The tweets of a little song sparrow and its 'bird brain' are a lot more
complex and akin to human language than anyone realized. A new study finds
that male sparrows deliberately shuffle and mix their song repertoire
possibly as a way to keep it interesting for their female audience.
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The research, from the lab of Stephen Nowicki, Duke University professor
of biology and member of the Duke Institute for Brain Sciences, and
colleagues at the University of Miami, shows that singing males keep
track of the order of their songs and how often each one is sung for up
to 30 minutes so they can curate both their current playlist and the
next one. The findings appear in Proceedings of the Royal Society Bon
January 26.
Song sparrows are a common songbird throughout North America, but only
males sing. They use their song to defend their turf and court mates.
When wooing, song sparrows belt up to 12 different two-second songs,
a repertoire that can take nearly 30 minutes to get through, since they
repeat the same song several times before going on to the next track. In addition to varying the number of repeats, males also shuffle the order
of their tunes each time they sing their discography. However, a big
unknown had been whether males change up their song order and repeats
by accident or by design.
To get some data on whether or not the birds intentionally shuffle and
mix their tunes, Nowicki's long-time collaborator William Searcy, the
Maytag Professor of Ornithology in Biology at the University of Miami,
loaded up the recording gear, trekked out to the backwoods of northwest Pennsylvania, set up mics pointed to the trees and patiently waited for
five hours a day.
Nowicki says that fieldwork like this isn't for everyone, "I would never
use the word boring, because it's relaxing if you like being out in
the field and it's a nice day and you've got your parabolic microphone
and you're pointing it at a song sparrow for hours. Some people would
find that boring. I and certainly Bill would find that meditatively
relaxing. The only thing that happens is sometimes your arm gets tired."
After recording the full suite of songs from more than 30 birds, the team
pored over visual spectrographs of the trills and analyzed how often each
song was sung and in what order. The first clue that males keep tabs on
their tweets to avoid repetition was that much like a Spotify playlist,
males generally sing through their full repertoire before repeating
a song.
==========================================================================
The researchers also found that the more a sparrow sang a given song,
the longer he took to get back to that song, possibly to build up hype
and novelty once that song was played again. For example, if a male sang
Song A 10 times in a row, he'd sing even more renditions of his other
songs before returning to Song A again. Alternatively, if Song A was
only warbled three times during a set, then a male song sparrow might
recite a shorter rendition of the rest of his repertoire in order to
return to the still novel and underplayed Song A.
Taken together, these findings demonstrate that song sparrows possess
an extremely rare talent with an equally uncommon name: "long-distance dependencies." It means that what a male song sparrow sings in the moment depends on what he sang as much as 30 minutes ago. That's a 360 times
larger memory capacity than the previous record holder, the canary, who
can only juggle about five seconds worth of song information in this way.
While impressive, the implications from this work for humans are less
clear. It does suggest that the order of words in human language, which
is similarly impacted by long-distance dependencies may not be as unique
as once thought.
It remains to be seen whether better shuffling ability gives males an
advantage at finding love. Perhaps females maintain interest in a mate
who mixes it up more, and are less likely to sneak off with another
male. As with daytime talk shows, paternity tests are a good proxy for
monogamy in birds, so counting how many chicks are sired by a female's
nest mate versus another bird in the neighborhood may be a future project
for Nowicki's team.
For now, Nowicki emphasizes it's just speculation whether these shuffling
song sparrows give Spotify a run for their money to keep a female's
interest, but does highlight our similar approach at the gym.
"You've got your playlist for running and the reason you've got that is
because running is kind of boring. You know that these 10 songs are going
to keep you motivated, but if you are going to run for 20 songs long,
why not shuffle it so the next time you don't hear the same songs in
the same order?" Support for the research came from the Office of the
Provost, Duke University, and the Robert E. Maytag Professor Research
Fund of the University of Miami.
========================================================================== Story Source: Materials provided by Duke_University. Original written
by Dan Vahaba. Note: Content may be edited for style and length.
========================================================================== Journal Reference:
1. William A. Searcy, Jill Soha, Susan Peters, Stephen Nowicki. Long-
distance dependencies in birdsong syntax. Proceedings of the Royal
Society B: Biological Sciences, 2022; 289 (1967) DOI: 10.1098/
rspb.2021.2473 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/01/220126122443.htm
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