A new study has uncovered some interesting behaviors by a parrot that are pretty fascinating — and pretty gross. And it came out of the amazing discovery that these parrots are actually using tools.

Scientists have found evidence of the first “grinding” tool used by a non-human: greater vasa parrots (Coracopsis vasa) have been found using pebbles to grind supplements out of shells, according to a Washington Post report.

The study, published by researchers from the University of York and University of St. Andrews in the journal Biology Letters, examined a set of 10 captive greater vasa parrots over eight months. They found that half of the parrots broke apart seashells in their cages using their beaks to get their calcium, but the other half used either pebbles or date pits to grind the shells into a powder and then licked up their calcium straight from those tools.

Greater vasa parrot, one of two species of vasa parrot (the other being the lesser vasa parrot), are found in Madagascar and the Comoros off the East Coast of southern Africa.

The scientists also found that these parrots would “borrow” tools from each other a lot, with a bird approaching group member sand grabbing the tool straight from their beak to use on their own shells.

Tool transfer may be even more fascinating than tool use itself, as it shows that parrot independently recognize the utility of the tool and may indicate the birds are passing the skill on to other individuals.

The study is interesting not just because of the tool use but also because of the parrots’ natural drive for calcium, which scientists hope to understand better. While it’s natural that birds should want calcium as it is necessary for good eggshells, four out of the five parrots who used the tools were male, and since they don’t lay eggs, they shouldn’t need the calcium.

Scientists think the answer might lie in the birds’ puke — males might be licking up the vital substance to puke it back up to their mates. This could help ensure successful matings, and could explain why calcium scraping was more common in the weeks leading up to the breeding season, according to the report.