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.
Really enjoyed this normal post. It’s a bizarre way of eating but it sure is efficient on the front end. I would really enjoy the access you got to those beautiful birds.
Thanks! Yes, I’m sure you could have taken really stunning photos if you had been where I was – I would have liked to see those photos!
I’m so jealous! (Does that make me weird? lol)
By the way, I have a photo of some pellet-like things that I am wondering about, maybe they are pellets (or droppings) from some kind of bird. They are made of fiber and are smaller than the ones in your photos. I’m the one who sent you the photos of the deformed junco a couple of years ago. Hope you don’t mind but I’m going to send you a photo over email, thanks :)
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