Of the more than 300 parrot species, only four have been seen using tools. In the wild, hyacinth macaws break open nuts with leaves and sticks, and black palm cockatoos drum on trees with rocks and empty nut shells. And in captive laboratory settings, keas use sticks to rake in nuts that are out of reach, and Goffin’s cockatoos do the same with wood tools they manufacture. Now, researchers have added another species to this short list: the greater vasa parrots (Coracopsis vasa) of Madagascar. The scientists made their discovery while video recording the behaviors of 10 of the birds housed together in an aviary at Lincolnshire Wildlife Park in the United Kingdom. From March to mid-April 2013, prior to the breeding season, five of the birds occasionally picked up pebbles or date pits from the floor of the enclosure and used these to scrape inside cockle shells, or to break off bits of the shells. The shells are part of a mix of soil, wood chips, and pebbles, and are there as a source of calcium for the birds. By grinding the pebbles or pits inside the shells (as shown in the video), the birds made a calcium powder—the first time that any animal, other than humans, has been seen using a grinding tool, the scientists report online today in Biology Letters. The parrots ate the calcium powder and the bits they broke off the shells. Many female songbirds consume calcium from shells before the breeding season, because they cannot store the chemical in their skeletons but need it to produce eggs. But four of the five greater vasa parrots that used the tools and ingested the calcium were males. The scientists suspect that because these male parrots regurgitate food to feed the females during courtship, copulation, and incubation, they may be providing the calcium to their mates indirectly. Chickens are known to better retain calcium if it’s given to them either ground or as small particles, so it may be that the male greater vasa parrots are grinding and breaking the seashells to also provide their females with high-quality calcium.
(Video credit: Megan Lambert)