Barfing Bird

Parts of food that animals can’t digest usually end up in their poop. But that’s not the case with owls. Instead, these birds throw up a pellet, or wad of indigestible material, containing the leftover bones, fur, and feathers of prey they’ve eaten. “Owls typically regurgitate one or two pellets a day, depending on how much they eat,” says Beth Mendelsohn, a wildlife biologist with the Owl Research Institute, in Montana.

Owls eat frogs, lizards, insects, small rodents, and smaller birds. Once an owl swallows its prey, the meal travels into the first section of the bird’s stomach. There, digestive fluids begin to break down the food. It then moves into the second part of the owl’s stomach, called the gizzard, for more digesting. Bits of bones, beaks, fur, feathers, teeth, and claws stay in this organ, where they are compacted into a tight mass the owl coughs up later.

Owls have to empty the remnants of a previous meal from their stomachs before they can eat again. Small owls, like the elf owl, produce pellets no bigger than the tip of your pinky. Big owls, such as the snowy owl, can make pellets longer than your thumb. The birds cough up a pellet about six hours after eating.

Scientists collect owl pellets and analyze the leftover bits of prey inside. The contents can tell researchers a lot about the birds’ eating habits. Sometimes, an owl pellet contains an entire skeleton from the previous meal. While it might seem gross, “dissecting the pellets is a good way to learn about owls and the prey that live in their area,” says Mendelsohn.