By Tamarah Feder
Pretty plumage alone just won’t cut it in some parts of the avian world. For certain bird species, it takes a whole song and dance – American Idol style.
Neeltje Boogert, who recently earned her PhD in Biology, studies song birds and says that although we still can’t tell what exactly they’re singing, it is apparent that their songs – and the ways in which they sing them – are critical for many birds to find true love.
The female Zebra Finch of Australia, for example, likes male counterparts to show off by belting out the same song, in the same way, over and over again like a welcome earworm. That may sound mind-numbingly simple, except that the female wants that tune to be a structured but wildly inventive avian jazz tune. No simplistic banging out of Chopsticks allowed. To her, musical virtuosity demonstrated through structure, speed and note arrangements suggests he is focused on courtship and has the time, resources and health to devote to singing. Though he may try out variations on a theme of his signature song in the company of his birdie buddies, the song he sings to woo a female is for her ears only. That kind of focus translates into an interesting partner who will stick around with her and the chicks.
To ensure he gets her attention, these little male Zebra Finches like to get all up in the face of their female judges. According to Neeltje, “The male has to really work it or the female may just go “ ‘meh,’ and fly away.”
Nightingales, on the other hand, are like the piano player in a bar. Their repertoires are so extensive that scientists have stopped counting how many songs they sing.
“We think male repertoire size can keep the female Nightingale interested as a vast range of songs in other species, such as starlings, has been shown to correlate with mating success,” said Boogert. “What we don’t know is whether the repertoire alone is what determines success or if there might be something else like a little dance to go with the song, as is the case for male Zebra Finches.”
Listening is as important a quality as performing in some male birds such as Cowbirds. “The male adjusts his song according to signals the female gives as to which notes she likes,” says Boogert.
Male-female interactions are paramount in effective courtship. Boogert illustrated the point by describing a study of female Zebra Finches watching a video of a male songbird singing. “The females would express interest but when they realized the male wouldn’t engage, they would just fly away.”
Guess he’s just not that into you.
And then there are the xenophobes. Within the Song Sparrow species, regional accents are very important so it is hard, if not impossible, for Song Sparrows from Philly to hook up with a New York City Sparrow. The reason has to do with a sort of language barrier. “When songbirds are chicks they learn the songs from the adults in their region,” Boogert explained. “It becomes their culture, so when they hear a bird from somewhere else it’s like they’re singing in a foreign language so the chances of mating are rather low.”
Though the song is important in determining overall compatibility in a potential mate, it’s really about the whole package. While Zebra Finches insist on stage time to ensure the full effect of their performances, females in most other song bird species might flitter toward a beautiful song they hear in the distance – only to be pleasantly surprised (or disappointed) upon seeing the singer. Song quality is hard to fake, so males that sing songs of superior quality will often be stronger, have richer territories, be better fathers and live longer than those with lighter tunes.
But sometimes singing your heart out isn’t enough. Boogert recounts witnessing the humiliation of one Zebra Finch. “I was recording in the field and this one male kept trying to sing his song to female after female, but none of them showed any interest. It wasn’t a very good song. So sad.”