Tool-Using Parrots Use Pebbles to Grind Seashells
In the spring of 2013, Megan Lambert noticed the greater vasa parrots of Lincolnshire Wildlife Park doing something odd. They looked like they were licking the cockle shells that lined the floor of their outdoor enclosure. But when Lambert looked closer, she noticed that they were holding a pebble or date pit in their beaks, and rubbing these against the shells.
They were using tools.
Several birds can use tools. Woodpecker finches prise grubs from wood with twigs, New Caledonian crows do the same, Egyptian vultures drop rocks onto eggs to crack them open, and rooks can raise the water level of a pitcher by dropping stones into it, Aesop-style. But among the 300 species of parrot, tool use is relatively rare. Black palm cockatoos use rocks to drum on tree trunks, while hyacinth macaws use sticks to prise open nuts. The kea, a delightfully mischievous New Zealand parrot, can use and make tools in the lab, but no one knows if they do so naturally.
Thanks to Lambert’s observations, the greater vasa parrot joins this exclusive club. Native to Madagascar, the greater vasa is a bit of a goth parrot, eschewing the vibrant hues of its relatives in favour of black and dark grey plumage. They’re sociable and inquisitive, and will often explore and manipulate objects in captivity; while watching them, Lambert saw one thread a twig through the open links of a chain. That seemed like play. By contrast, the thing with the seashells was probably more purposeful.
Seashells are made of calcium carbonate, and birds need calcium to build the shells of their eggs. Lambert thinks that the vasas were using the pebbles and pits to grind down the cockles and liberate the calcium within them. Other egg-laying animals, including sandwich terns and gopher tortoises, have been seen eating seashells, presumably for the same reason. But the vasas are the only ones known to process the shells. “That’s particularly interesting because humans are the only other animals known to use tools for grinding,” says Lambert.
But if that’s the case, why is it that only male parrots ground the seashells? If they’re trying to get at calcium for egg-laying, surely the females should be at it? Possibly, but during courtship and sex, vasa males spend a lot of time feeding females with regurgitated meals. Perhaps the calcium content of those fluids is a signal of the male’s quality as a mate?
Regardless, the behaviour is certainly common. Over a few months, Lambert saw all ten of the park’s greater vasa parrots interacting with the seashells, and at least five of them grinding the shells with pebbles or pits. One particular bird, a male named JD, was an especially prolific tool-user.
He was also a prolific tool-donor. On 16 occasions, Lambert saw one of the female parrots nicking a tool from another—usually JD, who tolerated the “theft”. “It’s quite unique that tools are transferred directly between birds, as this is not commonly observed in the animal kingdom and may provide clues as to how this behaviour came about in the first place,” says Lambert.
So far, Lambert and her colleagues haven’t done any experiments with the parrots, which leaves a lot of unanswered questions. Do the birds learn to use the tools themselves, or do they pick it up from their peers? What’s the purpose of the behaviour, and does it actually influence the birds’ reproductive success? Do the parrots grind seashells, or use other tools, in the wild? And what else are these animals capable of?
Related Topics
Go Further
Animals
- Octopuses have a lot of secrets. Can you guess 8 of them?
- Animals
- Feature
Octopuses have a lot of secrets. Can you guess 8 of them? - This biologist and her rescue dog help protect bears in the AndesThis biologist and her rescue dog help protect bears in the Andes
- An octopus invited this writer into her tank—and her secret worldAn octopus invited this writer into her tank—and her secret world
- Peace-loving bonobos are more aggressive than we thoughtPeace-loving bonobos are more aggressive than we thought
Environment
- Listen to 30 years of climate change transformed into haunting musicListen to 30 years of climate change transformed into haunting music
- This ancient society tried to stop El Niño—with child sacrificeThis ancient society tried to stop El Niño—with child sacrifice
- U.S. plans to clean its drinking water. What does that mean?U.S. plans to clean its drinking water. What does that mean?
- Food systems: supporting the triangle of food security, Video Story
- Paid Content
Food systems: supporting the triangle of food security - Will we ever solve the mystery of the Mima mounds?Will we ever solve the mystery of the Mima mounds?
History & Culture
- Strange clues in a Maya temple reveal a fiery political dramaStrange clues in a Maya temple reveal a fiery political drama
- How technology is revealing secrets in these ancient scrollsHow technology is revealing secrets in these ancient scrolls
- Pilgrimages aren’t just spiritual anymore. They’re a workout.Pilgrimages aren’t just spiritual anymore. They’re a workout.
- This ancient society tried to stop El Niño—with child sacrificeThis ancient society tried to stop El Niño—with child sacrifice
- This ancient cure was just revived in a lab. Does it work?This ancient cure was just revived in a lab. Does it work?
Science
- The unexpected health benefits of Ozempic and MounjaroThe unexpected health benefits of Ozempic and Mounjaro
- Do you have an inner monologue? Here’s what it reveals about you.Do you have an inner monologue? Here’s what it reveals about you.
- Jupiter’s volcanic moon Io has been erupting for billions of yearsJupiter’s volcanic moon Io has been erupting for billions of years
- This 80-foot-long sea monster was the killer whale of its timeThis 80-foot-long sea monster was the killer whale of its time
Travel
- How nanobreweries are shaking up Portland's beer sceneHow nanobreweries are shaking up Portland's beer scene
- How to plan an epic summer trip to a national parkHow to plan an epic summer trip to a national park
- This town is the Alps' first European Capital of CultureThis town is the Alps' first European Capital of Culture
- This royal city lies in the shadow of Kuala LumpurThis royal city lies in the shadow of Kuala Lumpur