Quirks and Quarks

March 4: Owls' hunt under snow, elephant gardeners, bats' sensory moustaches, cockatoos use tools and more...

Songbirds swarm their predators and seals appreciate a good rhythm

Songbirds swarm their predators and seals appreciate a good rhythm

Close up of the face of a great gray owl including large yellow eyes and beak
The large facial disk of the great grey owl acts like an antenna to help listen for voles under the deep snow (James Duncan)

On this week's episode of Quirks & Quarks with Bob McDonald:

Owls zero in on their prey under snow by eavesdropping on the sounds they make

The great grey owl is a specialist in hunting voles that live under the snow. The owl's large facial disk acts like an antenna to help tune into vole's digging and chewing sounds. Using special recording equipment, Christopher Clark from the Animal Aeroacoustics Lab at the University of California Riverside figured out that unless those noises were heard directly overhead, the sounds become muffled and change the direction it travels through the snow. This explains why the owls were most successful when they made their predatory plunge into the snow straight downward over the location of the vole. His research was published in Proceedings of The Royal Society B.

Elephant behaviour helps to maintain healthy, carbon-rich forests 

Forest elephants are playing an outsized role in mitigating climate change, so we need to protect their endangered populations to help combat global warming. That's according to a new study by Stephen Blake, an assistant professor of biology at St. Louis University. By pruning the forests in places like Africa's Congo basin, they allow for the trees that suck up the most CO2 to flourish. Elephants destroy mostly low carbon density trees by eating or trampling them. This means that the high carbon density trees thrive because they have less competition. 

A close up of a gray elephant peering through the leaves of trees in the forest
A forest elephant makes its way through an African rainforest on way to helping save the planet (Stephen Blake)
The 'sensory moustache' that helps bats find sweet snacks 

Biologist Eran Amichai studied the feeding habits of the nectarivorous Pallas's long-tongued bat using high-speed videography and a custom-made glass "flower." Playing back videos of the bats feeding at a fraction of their original speed revealed that they used brushlike forward-facing whiskers on the front of their muzzle to get to the nectar as quickly as possible. Amichai said that speed is likely important for the bats to avoid alerting nearby predators and to conserve energy as they hover in flight. These findings were published in the Proceedings of the Royal Society B: Biological Sciences.

Nectarivorous bats use sensory whiskers to feed on flowers

3 months ago
Duration 1:50
Feisty songbirds swarm their predators — but only when the time's right

In a recent study in the journal Frontiers in Ecology and Evolution, researchers describe what happened to birds in the area when they played northern pygmy owl calls through a loudspeaker in the Pacific Northwest forest. For the most part, the call was enough to scare off nearby songbirds, which make up the owl's diet. But sometimes, the songbirds defied the unwritten laws of nature that call for prey to flee. Instead, they chose to fight and together mobbed their perceived attacker. Wildlife biologist Madeleine Scott said that these mobbing events were more likely to happen during the spring and summer seasons, when food is more abundant for the songbirds. 

An owl sits on a tree branch.
Northern pygmy owl diets consist of small rodents and songbirds, with the balance shifting towards hunting birds in spring and summer seasons. (W Douglas Robinson)
Cockatoos have a handy tool belt to fish for cashews 

Results of a Current Biology study place Goffin's cockatoos on a short list of non-human animals that can use tool sets. In a series of experiments at the University of Veterinary Medicine Vienna lab, the cockatoos had to use tools to puncture through a transparent membrane inside a plastic box and extract a cashew. The cockatoos quickly mastered these tasks, sometimes in less than a minute. Evolutionary biologist and first study author Antonio Osuna-Mascaró said these observations of the cockatoos offer insights into the process by which humans learn to use tools. 

A white parrot uses a pink straw to access food placed in a transparent plastic box.
Goffin's cockatoos are the only non-primates to demonstrate the ability to use and transport tool sets. (Thomas Suchanek)
Seals may not tap their toes, but they do appreciate a good rhythm 

If you want insight into the evolution of our human appreciation for music, you study seals, of course! Seals are among the very few mammals that have the capacity to modify their own vocalizations; there was even a seal that learned to "speak," imitating human speech. Laura Verga, a cognitive neuroscientist from the Max Planck Institute for Psycholinguistics, wanted to know how other mammal species reacted to rhythm. After playing back vocalizations of pups to seals that were organized to be rhythmic or non-rhythmic, faster or slower, or long or short, she found the rhythmic vocalizations got much bigger spontaneous reactions from the seals than the non-rhythmic playbacks. 

Two harbour seals are chilling out on a beach.
Researchers have found that harbour seals have an innate appreciation for rhythm. (Henry Nicholls/Reuters)
Listener Question: Why can't waste plastic be dumped into volcanoes?

A listener asks: Why couldn't all the surplus and waste plastic on Earth be collected and deposited into large volcanoes?

For the answer we hear from Love-Ese Chile, sustainable plastics researcher at Regenerative Waste Labs in Vancouver.

A pile of various plastic waste  products on a stoney beach
A listen wondered why plastic waste couldn't simply be collected and dumped into an active volcano (Cpifbg13/Shutterstock)