LONDON, Feb 20: Some birds may have the natural ability to learn to avoid foods that taste disgusting and are potentially toxic by watching videos of each other eating, according to a new study.
Seeing the ‘disgust response’ in others helped the birds blue tits and great tits, native to the European continent, recognise distasteful prey by their peculiar markings without having to taste them, the study, published in the Journal of Animal Ecology, noted.
The researchers, including those from the University of Cambridge in the UK, said this trait can potentially increase both the birds’ and their prey’s survival rate.
According to the study, blue tits (Cyanistes caeruleus) learned best by watching their own species, whereas great tits (Parus major) learned just as well from great tits and blue tits.
The scientists said the birds can also decrease the likelihood of bad experiences — and potential poisoning — by watching others.
They said such social transmission of information about novel prey may have significant effects on prey evolution, and help explain why different bird species flock together.
“Blue tits and great tits forage together and have a similar diet, but they may differ in their hesitation to try novel food. By watching others, they can learn quickly and safely which prey are best to eat,” said study co-author Liisa Hamalainen from the University of Cambridge.
“This can reduce the time and energy they invest in trying different prey, and also help them avoid the ill effects of eating toxic prey,” Hamalainen said.
The study revealed that using social information to avoid bad outcomes is especially important in nature.
Many insect species, such as ladybirds, firebugs, and tiger moths have developed conspicuous markings and bitter-tasting chemical defences to deter predators, the scientists said.
But before birds learn to associate the markings with a disgusting taste, these species are at high risk of being eaten because they stand out, they added.
“Conspicuous warning colours are an effective anti-predator defence for insects, but only after predators have learnt to associate the warning signal with a disgusting taste,” Hamalainen said.
“Before that, these insects are an easy target for naive, uneducated predators,” she added.
In the study, the researchers showed each bird a video of another bird’s response as it ate a repulsive prey item.
The TV bird’s disgust response to unpalatable food — including vigorous beak wiping and head shaking — provided information for the watching bird, the study noted.
The scientists could control the information each bird saw by employing videos.
The ‘prey’ shown on TV consisted of small pieces of almond flakes glued inside a white paper packet, they said, adding that in some of the packets, the almond flakes had been soaked in a bitter-tasting solution.
Black symbols printed on the outsides of the packets indicated palatability — tasty ‘prey’ had a cross symbol that blended into the background, and disgusting ‘prey’ had a conspicuous square symbol, the researchers said.
The TV-watching birds, they said, were presented with the different novel ‘prey’ that was either tasty or disgusting, to see if they had learned from the birds on the TV.
Both blue tits and great tits ate fewer of the disgusting ‘prey’ packets after watching the bird on TV showing a disgust response to those packets, the study noted.
According to the researchers, birds, and all other predators, have to work out whether a potential food is worth eating in terms of benefits — such as nutrient content, and costs — such as the level of toxic defence chemicals.
By watching others to learn better food preferences can help the predators learn to avoid unpalatable foods, they said. (PTI)
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