Because an owl, like many other birds, cannot chew its food before eating, it must swallow its prey whole. As a result, the owl will swallow many things it cannot digest. After eating, an owl will regurgitate the parts that it could not digest in the form of pellets. Owl pellets are made out of bone, teeth, fur, hair, feathers and other parts of an owls prey that cannot be digested. Different owl species will regurgitate different sized pellets. Larger owls will tend to make larger pellets. By dissecting and studying owl pellets, scientists and students are able to learn about what an owl has recently eaten. By understanding the owls diet, scientists are able to better understand the food chain and the ecosystem the owl lives in. In addition, the owl pellet itself is an ecosystem that sustains life for bacteria, moths, beetles and fungi. Clothes moths are often found around owl pellets because their larvae will feed on the fur and feathers that the owl could not digest. These larvae will also undergo their metamorphosis near the pellet because they make their cocoons out of fur.
An owl pellet dissection is very easy and straightforward to conduct. An owl pellet dissection kit will include an owl pellet, plastic forceps, a wooden probe, a dissection guide, a magnifying glass, an identification key and a bone sorting chart. Students should start the owl pellet dissection by measuring the length, weight and mass of the pellet. By taking a measurement of the size of the pellet, students are then able to hypothesize which species of owl made the pellet. Using the forceps and the probe, students should then carefully break the pellet apart. After the pellet is broken apart, students should use tools in the owl pellet dissection kit to separate and clean off bones for identification. Commonly identified bones include skulls, jaws, scapulae, forelimbs, hindlimbs, ribs, vertebrae and pelvic bones. Students can use their bone sorting charts and identification charts to figure out what each bone is and what species each bone belongs to. Students should be able to find bones belonging to other small birds and rodents.
Owl pellet dissections are useful in teaching students about the digestive system of owls and the owls ecosystem. In addition, these dissections can help students understand the food web of the ecosystem that owls are a part of.