Tag Archives: sparrow

Avian earworm: ‘viral’ bird song is shifting tune preferences among Canadian sparrows

Most birds have very distinct calls that usually stay the same, making it easy for bird watchers to recognize a species without seeing it. But the tunes can actually change, according to a new study, which tracked how the song of one sparrow went viral and ended up wiping out a historic bird song.

Credit Wikipedia Commons

The study showed that the white-throated sparrows (Zonotrichia albicollis) from British Columbia to central Ontario have abandoned their traditional three-note-ending song in favor of a unique two-note-ending variant. Nevertheless, researchers still don’t know what made the new song so captivating.

“As far as we know, it’s unprecedented,” said in a statement senior author Ken Otter, a biology professor at the University of Northern British Columbia. “We don’t know of any other study that has ever seen this sort of spread through cultural evolution of a song type.”

An ornithological earworm

While rare, sometimes bird species do change their songs and this usually happens only in local populations, leading to regional dialects.

Back in the 1960s, the Canadian sparrows used to whistle a song that ended in a three-note triplet. By the time Otter moved to Canada in the 1990s the two-note ending was already present in local populations. “They were singing something atypical from what was the classic white-throated sparrow song across all of eastern Canada,” he said.

For their study, Otter and his team took advantage of a network of citizen scientist birders in North America, who had uploaded recordings of sparrow songs to online databases. This helped to track the doublet-ending song, which they found was spreading fast across Canada.

“Originally, we measured the dialect boundaries in 2004 and it stopped about halfway through Alberta,” Otter said. “By 2014, every bird we recorded in Alberta was singing this western dialect, and we started to see it appearing in populations as far away as Ontario, which is 3,000 kilometers from us.”

The researchers predicted that the sparrows’ overwintering grounds had something to do with the spread of the two-note ending. Juvenile males could have been picking up new songs when thy overwinter with birds from areas with other dialects, Otter argued.

To check if this was true, the researchers attached geolocators to the sparrows to see if western ones who knew the song might share it with eastern populations. This was indeed the case. Not only the song was spreading across the continent but it also was replacing the triple-note ending that had persisted for many decades.

The new song didn’t give male birds a territorial advantage over male counterparts, the study showed. Nevertheless, the researchers still want to continue looking at whether female birds have a preference between the two songs. “In many previous studies, the females tend to prefer whatever the local song type is,” said Otter.

Now, another type of song has appeared in a western sparrow population whose early spread may mirror that of the doublet-note ending. Otter is looking forward to continuing his investigation and check how this new song shifts in real-time, working alongside the network of citizen scientists.

“By having all these people contribute their private recordings that they just make when they go bird watching, it’s giving us a much more complete picture of what’s going on throughout the continent,” he said. “It’s allowing us to do research that was never possible before.”

The study was published in the journal Current Biology.

Europe has 421 million fewer birds than 30 years ago

Europe has an estimated 421 million fewer birds than it did 30 years ago, a startling study has found. The current trends show an unsustainable development, and if things continue with ‘business as usual’, we can expect even more decrease and even extinctions.

Some of the birds that have suffered the most alarming declines are some of the most well known species on the continent: right now, we have 147 million less sparrows (a decline by 62%). Populations of starling also dropped by 53%, and skylark numbers went down by 46%.

A skylark, one of the 144 species looked at in the study. The skylark population has fallen by 46% since 1980. Photograph: Michael Finn/PA

“This is a warning from birds throughout Europe. It is clear that the way we are managing the environment is unsustainable for many of our most familiar species,” said Richard Gregory of the Royal Society for the Protection of Birds, which co-led the study. “The conservation and legal protection of all birds and their habitats in tandem are essential to reverse declines.”

The study analyzed bird numbers from 1980 to 2009; they split the birds up into four groups based on rarity. They found that while rare birds have increased slightly by 21,000, the most common birds have suffered a decline of 350 million. This shows that while conservation efforts have been moderately successful, we are taking an approach that is too narrow and highly detrimental to common birds.

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Today, we have 147 million less sparrows than we did just 30 years ago. Image via Wiki Commons.

“The focus up to this point has very much been on conserving rare species,” says the lead author, Richard Inger, from the University of Exeter. “That’s what it should be, in many ways, but the issue there is that if you’re not careful, you can spend all of your conservation dollars on just protecting the rare things. You can take your eye off the ball, if you will.”

Most notably, the blackcap, a rare bird, has made a resurgence, more than doubling its population. Other notable growths are the common chiffchaff (up 76%) and wren (56%). But if you look at it in raw numbers, this doesn’t mean that much. Also, protecting small populations of rare birds is much easier than adopting general conservation measures to protect larger populations.

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“If the species is very localised, there may be very strong conservation measures,” says Graham Madge, a spokesman for the Royal Society for the Preservation of Birds, which collaborated on the study. “Whereas for a species like the skylark, which will occur in most countries across Europe, it’s much harder to bring in a rescue measure because it requires the rollout of broad, landscape-scale conservation measures.”

The blackcap is among the few species making a resurgence in recent years, likely due to conservation efforts. Photograph: Andrew Darrington/Alamy

The most common cause of decline in numbers was agricultural intensification; this process has destroyed much of the birds’ habitat, as well as the areas where they eat and breed. But it’s not just agriculture which is causing the problems – there seems to be a generalized issue with growing cities.

“People have tended to concentrate on farmland, but some of these species that don’t use farmland habitats at all are also declining. It’s a sign of wider scale environmental issues, such as increases in urbanisation, and the only way we’re going to protect these widespread species is a more holistic approach to how we manage the environment in general.”

So, what can be done? The first step would be to understand just how big the problem is, and this is what this study has done. Then, not scientists, but policy makers need to acknowledge the situation and start acting on it. A good place to start would be encouraging wildlife-friendly farming. The thing is, we have to understand that this is not solely about protecting birds – bird species provide a huge number of ecosystem services, such as decomposition, pest control, pollination, and seed dispersal. Since common species exist in higher numbers, they play a bigger role in maintaining the ecosystem as well. The decline in their numbers equals not only environmental, but also economical disaster.

“This was a bit of a wake-up call really,” says Inger. “We knew we were going to see a big decline in bird populations, but to see how big that number really was and how focused the declines were on this small number of common species was really very surprising.”