All those amazing bird tweets that everyone finds so musical are more than just a melodious tune. In fact, a new study has found that male song sparrows can deliberately mix and shuffle their song repertoire, precisely to keep their female counterparts interested.
The study research, conducted in the lab of Duke University professor of biology and member of the Duke Institute for Brain Sciences, Stephen Nowicki, and his colleagues from the University of Miami, found that the singing male sparrows actually keep track of their songs, the order in which they sing them, as well as how often they sing the same one, for up to 30 minutes. And this is possibly so that they plan out what they sing at the moment, as well as what they plan to sing afterwards.
While song sparrows are one of the most common songbirds all throughout North America, it’s only the males that can actually sing. Not only do they sing to court females, but they also use their “voices” to defend their territories.
Incredibly, when a song sparrow woos a partner, they can sing up to 12 different two-second songs, which can take almost 30 minutes to get through since they tend to repeat the same song over and over again before they move on to their next anthem. Plus, aside from changing up their number of song repeats, these male sparrows also shift the order of their songs every time they sing, but one thing that’s still not necessarily known is if these male birds change their song order and repeat them by accident, or if it is deliberate.
In order to better understand if birds are intentionally mixing and shuffling their tunes, the Maytag Professor of Ornithology in Biology at the University of Miami, William Searcy, who is Nowicki’s long-time collaborator, decided to head outdoors to the backwoods of northwest Pennsylvania with loads of recording gear, and set up microphones which they point towards to trees to record the birds, sometimes waiting for up to five hours a day.
Nowicki explains that this type of fieldwork isn’t always for everyone. He shares, “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.”
The team spent hours in the woods, but managed to record the full suite of songs from over 30 birds. After which, they dissected and searched through all the visual spectrographs of the trills in order to analyze how often each and every song was sung, as well as the order of which they were tweeted. One of their first clues that males are very much aware of their songs and avoid reputation, just how your favorite Spotify playlist does, is that the ‘males generally sing through their full repertoire before repeating a song.’
The group also discovered that the more one of the male birds sang a particular song, they would take longer to go back to that song, which they believe could probably be so they could ‘build up hype and novelty once that song was played again.’
They further explained, if a male bird sang “Song A” for at least 10 times in a row, he would sing even more variations of this other songs first before going back to Song A. Moreover, if Song A was sung at least 10 times in a row, he would sing more renditions of this other songs before choosing to go back to Song A once more. But on the other hand, if Song A was only sung three times during the birds “first set,” then he may just ‘recite a shorter rendition of the rest of his repertoire in order to return to the still novel and underplayed Song A.’
When all these findings were taken into consideration, they proved that song sparrows have an incredibly rare talent that is actually known as “long-distance dependencies.” What this means is that what a male song sparrow may have sung at the moment will depend on what he sang, possibly over 30 minutes before that. This proves that these birds have a ‘360 times larger memory capacity than the previous record holder,’ which was the canary, who reportedly can only handle around five seconds worth of song information in the same way as the sparrow.
Although this is quite impressive, the implications from this work, when it comes to humans, is not as clear. But what it does show is that just like the order of words in human language, which is considered similarly impacted by long-distance dependencies as well, is not as exclusive to humans as once believed.
Although there is still uncertain whether the ability to shuffle things around better does actually give the males a greater advantage at finding a mate, there is a chance that the females to maintain their interest in a male mate with the ability to mix things up more.
Currently, Nowicki and team share that their theory is just speculation at the moment, and that these possible song-shuffling song sparrows have yet to prove their theory 100%, there is something to be said since humans take this same song-shuffling approach when they work out.
Nowicki shares, “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?”
See more about these amazing song sparrows in the video below.
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