As the wind picked up and chilly raindrops battered midterm-wearied faces, the student naturalists took shelter in a patch of conifers next to the McKnight Prairie. While idling beneath the safety of the canopy, they came across one tree, the base of which was littered with white droppings. Investigation check—pass. They discovered a cylindrical, dark grayish mass roughly the width of a palm. An owl pellet! The naturalists exclaimed before starting to pull the compact mass apart.

All birds have two parts in their stomachs: the glandular stomach, where digestive enzymes are secreted and the digestible parts of their food are liquefied, and the muscular stomach (also called the gizzard), where hard structures are ground down. For an owl, the gizzard compacts the indigestible fur, bones and teeth of their prey into a pellet, which is then regurgitated. Before the pellet from a previous meal is coughed up, an owl cannot take in more food. An owl generally produces two pellets a day while at roost, so an accumulation of pellets in one spot can be a good indicator of owl inhabitation.

The naturalists gingerly picked out a thumb-sized piece of upper jaw and a corresponding lower jaw. Skull identification check— pass. They recognized that the bones belonged to a pocket gopher, a squirrel-sized rodent that typically lives in underground tunnels in prairies. A pellet this size would likely belong to a larger owl species, such as the Great Horned Owl. Sure enough, as they looked up, a juvenile Great Horned was sitting comfortably in its nest, casting a wary eye towards the group of bipeds who were gazing up in awe.

Perception check — pass?

Kestrel Liu ’23, for the Cole Student Naturalists

Photo to include:

An Owl Pellet. Photo credit: Nancy Braker ’81