Small brown clumps of something on the ground. It could be animal scat, but no, it is something else entirely! Those of you who are faithful Arb Note readers will have read recently about how easily owl pellets can be found. In the Arb, if you simply look on the ground around the birds’ favorite roosts, which will be marked with telltale whitewash, you’re bound to find one. But what exactly is an owl pellet?
When an owl eats its prey, it swallows the prey whole. Without the ability to chew, it relies on its stomach, made of two chambers called the proventriculus and the gizzard, to break down the food. In the proventriculus, digestive fluids begin to process the prey. Next, in an owl’s gizzard, sand and gravel combine with muscle contractions to break it down more. It can then continue on for further digestion in the intestine and beyond. Digestible materials include muscle, skin, fat, and organs. On the other hand, teeth, claws, feathers, and other components that the owl’s stomach acids are not strong enough to break down must still be expelled.
Here, the pellet comes to the rescue. The gizzard compacts the indigestible material into a pellet, which then travels back into the proventriculus. There it can stay for up to half a day. While the pellet remains, the owl is not able to eat any more food, so the pellet must be regurgitated before the next time it eats. These pellets can then be discovered by interested Arb walkers, giving insights into the daily diets of our favorite nocturnal neighbors.
–Darcy Mishkind ’16, for the Cole Student Naturalists
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