If you’ve ever ventured beyond admiring the assorted dazzling plumages of birds or simply enjoying their symphony of warbles and melodies and carefully watched their behaviours, you might be amazed at some of their feats.
That’s what dedicated bird watchers have been doing for decades, and now a global analysis of more than 3800 foraging innovations, published in the journal Nature Ecology and Evolution, has found that more innovative bird species have a greater chance of survival.
The notion is hardly new, but observations from virtually all bird species, devotedly collated in a unique database over nearly a quarter of a century by Louis Lefebvre, from McGill University in Québec, Canada, has confirmed that the adaptive survival benefit of novel behaviours is robust.
Many birds adapt by incorporating new foods into their diet, like the Northern cardinals (Cardinalis cardinalis) seen sucking up nectar from shrimp plants for the first time.
But some innovations are extraordinary, says Simon Ducatez, first author of the paper, with species showing remarkable behavioural plasticity (innovation) to get their grub and demonstrating complex problem-solving abilities.
Great cormorants (Phalacrocorax carbo), for instance, have been seen opportunistically fishing in New Zealand when commercial ferries go past to take advantage of the strong currents, while green herons (Butorides virescens) use bread or insects as bait to catch fish.
Other ingenious behaviours include carrion crows (Corvus corone) spotted using cars to crack nuts or seashells, while corvids, raptors and gulls drop mussels on hard rocks to break them open.
Incredibly, bullfinches (Loxigilla barbadensis) in Barbados and blue-faced honeyeaters (Entomyzon cyanotis) in Australia’s Hunter Valley have been observed opening sugar packets on café terraces.
“So that’s a funny innovation,” says Ducatez. “While we don’t necessarily expect that specific innovation to bring a solid advantage to the individuals who are doing it, it’s a very good cue that the species is able to devise new behaviours if it has to or wants to, if it has the opportunity to do so.”
It also requires several steps, he notes, because they must associate the sugar packets with food then develop a behaviour that enables them to open them, a relatively complex feat for a bird.
Confirming the survival advantage of novel behaviours has presented a grand challenge until now, Ducatez says.
To do so involves observing individual behaviours and comparing different species under lots of different conditions to confirm and compare how novel they are.
“If, instinctively, a raven seems to be better able to devise new behaviours than, say, a partridge, how can this be formally measured?” he writes in a Nature blog post. “Louis’s innovation database was the perfect resource to address this question.”
Lefebre compiled the database by combing ornithology journals from every corner of the globe and recording every mention of a new or unusual behaviour, then determining whether it is indeed original.
“And the more a species is reported as behaving in a new way, the more likely it is to be able to develop new behaviours,” says Ducatez.
“Our idea here is that if you are able to devise new behaviours in general, new original ones, pretty unique ones, maybe you are also better able to devise new behaviours when you’re exposed to changes in the environment.”
Sourcing data on extinction risk from the International Union for the Conservation of Nature (IUCN), the team – from Canada, Spain and Sweden – ran a series of models that included potentially confounding variables including life history, geographic range and ecology of 8600 bird species.
No matter which way they built the models, the results consistently showed that more innovative species have lower extinction risk and more stable or growing populations.
The finding can help give clues to which species to target with conservation efforts, a growing imperative with the “biodiversity crisis” caused by an unprecedented level of anthropogenic threats that confront them.
But while behavioural innovation can help buffer some species to threats like habitat destruction, the team found there is little they can do in the face of overexploitation – by hunting, for instance – or invasive species.
Natalie Parletta is a freelance science writer based in Adelaide and an adjunct senior research fellow with the University of South Australia.
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