Birds can learn good eating habits from watching others, even without being present to experience the smells and sounds but some refuse to learn from non-members of their own species.
Poisonous or foul-tasting animals frequently warn predators by adopting bright colors, known as aposematism. Although these colors signal “don't eat me” to animals who know the deal, they also make the bearer particularly conspicuous to those unfamiliar with the signal, who will likely eat them. Biologists have been puzzled as to why this strategy works overall.
The more predators learn from each other, rather than having to try the bright thing themselves, the better aposematism is likely to work. Dr Liisa Hämäläinen of Cambridge University tested the capacity of two types of birds, blue tits and great tits, to learn from the experiences of others.
To make sure the birds were not using hardwired knowledge, Hämäläinen made food items out of almond flakes, sometimes soaked in a bitter solution, and placed a cross or a square on an outer wrapping depending on whether the unpleasant taste was added. The birds' reactions were filmed and shown to members of both their own and other species. According to Hämäläinen, both species paid plenty of attention to the screen when the feeding was shown.
Upon eating the bitter flakes the birds reacted with almost comical disgust, making a great show of their distaste, whose meaning their viewers recognized. In the Journal of Animal Ecology Hämäläinen reports birds steered well clear of the aposematic symbol in the video they had watched, lest they make a tit of themselves. “By watching others, they can learn quickly and safely which prey are best to eat. 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," Hämäläinen said in a statement.
Hämäläinen told IFLScience the negative reaction is “Mostly trying to get rid of the taste, for example by wiping their beaks.” Although she considers it possible these social birds have learned to overact to make sure their flockmates learn, she doesn't think there is any evidence solitary species are less dramatic.
Blue tits got the message when they watched fellow blue tits eat the artificial aposematic food, but seldom learned from great tits' reactions. However, great tits acquired knowledge from both species. The two birds often co-exist in the same space, and eat a similar diet, so Hämäläinen told IFLScience she doesn't know why learning between them only goes one way.
Perhaps if birds can learn a healthy diet from TV, humans might as well. For that, however, fruit and vegetable growers might need an advertising budget at least as large as the makers of unhealthy, brightly colored, but oh-so-tasty food items.