Today I submitted the Big Grant Proposal that I’ve been working on for a while. To celebrate this, because I am a normal person, I dissected some owl pellets.
These particular owl pellets were from Great Horned Owls—these ones, in fact:
When an owl eats something, it doesn’t digest the whole thing. The hard-to-digest parts—bones, fur, exoskeleton—get smooshed into a pellet in the gizzard and then regurgitated. These pellets are a record of what the bird has eaten.
I can guess that the pellets were from these particular owls because I found the pellets underneath the owls. There were a lot of pellets: clearly the owls have been using this roost for a while.
I collected three pellets to dissect. I was curious to see what these owls were eating, and owl pellets are hard to resist, with their mystery and tiny bones.
Dissecting a pellet just means pulling the matted fur apart and pulling bones out. Mostly the bones are disarticulated, but some vertebrae were still together.
The pellets weren’t all the same. Pellet #2, unlike the others, had a lot of little larvae in it. Sorry I messed up your home, larvae.
Pulling wriggling grubs out of skull eye sockets felt like Halloween come early.
Pellet #1 had some plant matter: grass, a few spiky little seeds. All of the pellets had a lot of dirt and tiny stones. I suppose if you’re eating rodents whole, you can expect to eat some dirt too.
I had seen seagull feathers scattered around the roost and was hoping to find some bird bones, but everything I could identify looked like rodent to me.
I found 8 skulls in my pellets. Two were very small, while the rest were maybe gopher or squirrel-sized—certainly not the largest prey these big owls can eat.
Because bones, especially mammal bones, are not my area of expertise, I’m going to see if I can get some friends to help identify the owl pellet bones, and will let you know the results.