Researchers have documented the use of tools by parrots. Captive greater vasa parrots, Coracopsis vasa, were observed using small pebbles and date pits to scrape calcium from shells for ingestion.

Psychologists from the University of York and University of St. Andrews say their findings -- published this week in the journal Biology Letters -- show for the first time the use of tools for grinding by nonhuman animals. Their observations are also one of only a few examples of tool sharing.

"The use of tools by nonhuman animals remains an exceedingly rare phenomenon," lead author Megan Lambert, a psychologist at York, said in a press release. "These observations provide new insights into the tool-using capabilities of parrots and give rise to further questions as to why this species uses tools."

The birds weren't equally resourceful. Over a period of several months, five of the ten parrots used tools to either grind or break apart the cockle shells.

Birds showed the most interest in the shells in the weeks leading up to mating, suggesting calcium supplementation is beneficial to the reproductive process.

Males appeared most interested in the shells and their calcium, but were frequently seen offering regurgitative feeding to their mates prior to copulation.

"Tool use could reflect an innate predisposition in the parrots, or it could be the result of individual trial and error learning or some form of social learning," Lambert explained. "Whether these birds also use tools in the wild remains to be explored, but ultimately these observations highlight the greater vasa parrot as a species of interest for further studies of physical cognition."

Study: Dogs offer foods to their friends
Vienna (UPI) Dec 16, 2015 - Few animals have been shown to exhibit cooperation on the level of human sharing -- assisting a fellow animal without necessarily benefiting or receiving anything in return.

Such cooperation is called prosocial behavior. Until now, prosocial behavior has only been confirmed among man's closest relatives, primates.

But new research suggests dogs are capable of prosocial behavior. Experiments showed dogs are willing to share food with their fellow canines, and are most generous toward those they're friends with.

To test dogs' propensity of generosity, researchers used a bar-pulling trick whereby a dog could pull on a lever to deliver a tray with food to a second dog. Donor dogs were shown how a pair of levers delivered either an empty tray or a tray with a treat on it to their canine neighbor.

The tests showed dogs were often willing to help out, and that they were more apt to assist their neighbor if they had met them before.

"Dogs truly behave prosocially toward other dogs," explained lead researcher Friederike Range, an animal behavior expert at the Messerli Research Institute in Vienna. "That had never been experimentally demonstrated before. What we also found was that the degree of familiarity among the dogs further influenced this behavior."

Control testing helped researchers confirm that the dogs weren't just pulling the tray for the fun of it -- when given the option, they knew to pull the lever to give themselves a treat. The fact that they were more willing to gift their friends a treat further confirms that point.

"This control excludes the possibility that the dogs did not pull on the tray out of fear of the unfamiliar dogs. Given the same situation, the dogs gladly gave themselves a treat," Range said.

"We were also able to disprove the argument that the dogs pulled the string less frequently because they were distracted by the unfamiliar partner during the test," he added. "Only rarely did a donor dog interact with the unfamiliar dog."

The research was published in the journal Scientific Reports.