If a little birdie in a tree has an upset stomach, this could be the reason why.
Scientists in Japan have found that snails eaten by birds are able survive the animal's digestive tract and emerge -- on the other end -- alive in the waste droppings.
Published in the Journal of Biogeography, the research observed the bird population of Japanese white-eyes and brown-eared bulbuls living on the island of Hahajima in the Western Pacific, the BBC reports.
The researchers from Tohoku University in Japan say that 15 percent of snails, known as Tornatellides boeningi, survive a bird's digestive system.
The snail's ability to pass through the gut alive could explain how certain populations are dispersed and connected within a given ecosystem.
"We were surprised that a high rate, about 15 percent, of snails were still alive after passing through the gut of [the] birds," researcher Shinichiro Wada told the BBC.
"This is the first study showing that birds can indeed transport a substantial [number of] micro land snails in their gut alive."
According to the study, one snail even gave birth to "juveniles" after enduring the digestive journey.
It is well known that birds disperse plant seeds by a similar process, leading to the spread of plant life in a region.
In this case, according to researchers, the snail's tiny size allows it to survive the digestive tract. Larger snails are more likely to have their shell damaged in the bird's stomach.