Hungry great tits hunt for hibernating bats
When food is precious, animals can resort to strange behaviours in order to satisfy their hunger. Take the great tit. Its usual diet of insects and creepy-crawlies is harder to come by in winter. But in one Hungarian cave, great tits, ever the opportunists, have learned to exploit a rich and unusual source of food. They kill sleeping bats.
Great tits are only about 5 inches long, but their prey – the pipistrelle bat – is smaller still, just an inch or two in size. The bats spend the winter months hibernating in rock crevices. They’re well hidden, but when they wake up, they start making noises and these are the telltale signs that the birds are listening out for. They hunt by flying slowly and systematically across the cave walls, eavesdropping on the bats’ noises, and killing them while they’re still woozy.
Peter Estok from Germany’s Max-Planck Institute for Ornithology spent two winters watching a group of around 50 great tits hunting for bats. Previously, there had only been a smattering of anecdotal evidence that this happened. In one case, a tit was found eating a dead bat outside a Polish cave, but it could well have been scavenging off an already deceased corpse. Then, thirteen years ago, Estok saw a great tit capturing a live bat in a Hungarian cave. He was intrigued and he returned to the cave several times for more observations.
Tits lack the obvious killing apparatus of birds of prey but their short beaks are strong enough to dismember a tiny pipistrelle. Estok saw several instances of actual kills and recovered a few carcasses that showed obvious bite wounds. The bodies were picked clean enough to suggest that the birds were killing the bats for food and not, say, to remove competition for roosting spots.
These attacks are driven by necessity. On days when Estok hung a feeder outside the cave entrance, provisioned with seeds and bacon, he saw only one instance of a tit killing a bat. Without the feeder, he saw 17 such incidents.
Estok even confirmed the tits’ hunting technique by recording the noises of waking bats and playing them back from a speaker hidden in the rocks. Around 80% of the birds reacted strongly to the sounds, approaching the speaker and investigating more closely. This is especially interesting because other studies have found that the calls of waking bats actually put off mammal predators – they tell them that the bats are awake and not susceptible to ambushes. But for birds, which can rival the bats in the air, these calls are far from a deterrent.
The odds of a great tit surviving for more than 8 years are one in a thousand. This means that the individual that Estok saw eating a bat in 1996 couldn’t possibly be part of the same group that he studied this time round. Has the bat-killing behaviour passed down through generations of tits as a local cultural tradition? It’s impossible to say for now, but there’s certainly precedence for this – British blue tits famously learned to open milk bottles to drink the cream at the top and the behaviour spread like wildfire across the country.
Reference: Biology Letters doi:10.1098/rsbl.2009.0611
Image: Great tit by Luc Viatour; bat from paper.
More reading:
Go Further
Animals
- These 'trash fish' are among Earth's most primitive animalsThese 'trash fish' are among Earth's most primitive animals
- These photos are works of art—and the artists are bugsThese photos are works of art—and the artists are bugs
- The epic migration of a 6-foot long, 200-pound catfishThe epic migration of a 6-foot long, 200-pound catfish
- Frans de Waal, biologist who studied animal emotion, dies at 75Frans de Waal, biologist who studied animal emotion, dies at 75
Environment
- Are synthetic diamonds really better for the planet? The answer isn't clear-cut.Are synthetic diamonds really better for the planet? The answer isn't clear-cut.
- This year's cherry blossom peak bloom was a warning signThis year's cherry blossom peak bloom was a warning sign
- The U.S. just announced an asbestos ban. What took so long?The U.S. just announced an asbestos ban. What took so long?
- The most dangerous job? Inside the world of underwater weldersThe most dangerous job? Inside the world of underwater welders
- The harrowing flight that wild whooping cranes make to surviveThe harrowing flight that wild whooping cranes make to survive
History & Culture
- Meet the powerful yokai that inspired the demon king in ‘Demon Slayer’Meet the powerful yokai that inspired the demon king in ‘Demon Slayer’
- A surprising must-wear for European monarchs? Weasels.A surprising must-wear for European monarchs? Weasels.
- Meet the woman who made Polaroid into a cultural iconMeet the woman who made Polaroid into a cultural icon
- Inside the observatory that birthed modern astrophysicsInside the observatory that birthed modern astrophysics
Science
- LED light treatments for skin are trendy—but do they actually work?LED light treatments for skin are trendy—but do they actually work?
- NASA smashed an asteroid. The debris could hit Mars.NASA smashed an asteroid. The debris could hit Mars.
- Humans really can have superpowers—scientists are studying themHumans really can have superpowers—scientists are studying them
- Why engineers are concerned about aging infrastructureWhy engineers are concerned about aging infrastructure
Travel
- Play and stay in the mountains of eastern Nevada
- Paid Content
Play and stay in the mountains of eastern Nevada - This couple quit the city to grow wasabi in Japan's mountainsThis couple quit the city to grow wasabi in Japan's mountains