How Do Owl Pellets Work?

Hello WSC fans, this is Leya Collins, Museum Supervisor here. One of the perks of being a supervisor is that I have the joy of assisting the education department with their many field trips every year. We see about 8,000 children every year who travel up to an hour away just to visit us! 

One of my favorite labs to teach during the field trips is the owl pellet lab. Before the pandemic hit I was fortunate enough to be able to teach one to some really enthusiastic and curious 2nd graders visiting the Western Science Center. To do this lab the children get tweezers, a wooden dowel, a magnifying glass, as well as identification tables to help them research what they find. All of our owl pellets are UV sanitized so they hold no germs, only specimens for our students to discover - which is important due to the nature of how owl pellets are formed! 

Owls are birds of prey that consume their meals (rodents and insects) but then are unable to process the fur, bone, and exoskeletal material, so it is collected in the proventriculus, or first stomach. The rodent or insect then receives HCL, hydrochloric acid, in the first stomach; then it moves to the ventriculus, also known as the second stomach or gizzard. All digestible material moves on into the small intestines, but the fur and bone material form a pellet that is then regurgitated. The entire process takes less than half a day and leaves behind some really interesting specimens! 

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During our last lab one student found insect mouth pieces, which in my experience teaching the labs is pretty rare. We know owls eat insects but due to the nature of their softer exoskeletons most parts do not survive the pellet forming process. The following pictures of the insect mouth parts as well as a vertebra were taken using a microscope with .1mm scale bar beside it. I’ve also added a photos of a large rodent skull found fully intact. Most skulls are damaged in the digestive process so it’s always a treat for the students to find one intact. After the lab students are able to take their specimens home to share with their families and most all are thrilled to do so!  

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