More Great Horned Owl Pellets at Columbus Park

It’s been a busy month at work, but this morning, for the first time in two weeks, I monitored birds at Columbus Park. I saw 13 species of birds, including a Red-tailed Hawk whose tail was a mix of banded juvenile feathers and bright red adult feathers. However, I did not see the on-again-off-again Great Horned Owl who sometimes roosts in an oak tree on the west side of the Park. (Read about it here.)

I always enjoy seeing the owl, but when the owl’s gone I’m not too sad, because then I can search for owl pellets under its roosting tree. The pellets I’ve found so far (shown in this post) contained a mix of medium and small mammal bones, but no teeth. So I figured the owl was feeding on squirrel, rabbit, or maybe possum-sized mammals. Since I can’t often identify bones to species, I was really hoping to find some owl pellets with teeth or jar bones, which I often can identify. Today I lucked out:

Pellets spit out by the Great Horned Owl who sometimes roosts in Columbus Park. The large, snow-crusted pellet on the right includes a lower jaw. (Taken with my iPhone.)

Here’s a closer look at the jaw:

I dug the jaw out of the frozen pellet so I could see the teeth. With the front gnawing teeth and grinding cheek teeth exposed, I recognized it as the mandible (lower jaw) of a Cottontail Rabbit. (Taken with my iPhone.)

Go here to see a photo of a complete Cottontail Rabbit skull with mandible.

This fall we had lots more rabbits than normal in Columbus Park, and I’d noticed gnawing damage to shrubs and small trees that was probably the work of rabbits. My neighbors in Oak Park had also noticed more rabbits in their yards this year and complained about damage to their gardens.  So, now there’s evidence that our Great Horned Owl is bringing the rabbit population back to normal.

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Here are links to information and activities about owl pellets:

• Wikipedia on pellets made by owls and other birds of prey

• A virtual owl pellet dissection

• A chart showing the kinds of bones found in owl pellets (pdf file)