Neighborhood Nature

Our Family's Nature Blog

No Owl Today, Just Fast-Frozen Owl Pellets December 16, 2009

Filed under: Animals,Birds,Seasons,Winter — saltthesandbox @ 7:12 pm
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The neighborhood crows and I were both disappointed that we didn’t find the Great Horned Owl in its usual roosting tree in Columbus Park. Here’s what the owl looked like yesterday afternoon — the third day in a row we had seen it in exactly the same spot in a White Oak tree:

Great Horned Owl roosting in a White Oak tree, Columbus Park, Chicago, Illinois, December 15, 2009.

Yesterday at 2:15 p.m. the Great Horned Owl was in its usual White Oak roost in Columbus Park.

This morning I looked at the same tree from every angle — and every tree around it — for 10 minutes and couldn’t find the owl. Then five minutes after I gave up a flock of Common Crows flew into the roosting tree and landed in its upper branches. These were tough crows! I had earlier seen them harassing first an American Kestrel and then a Red-tailed Hawk. I figured they knew something I didn’t — after all, crows first found this owl for me on November 24th. So, once the crows flew off, I went back to the roost tree and looked again.

Still, no owl.

I should have been disappointed, but I looked at the bright side. If the owl was in its roost, I would have backed off and left it alone. Since there was no owl to scare off, I could go look for owl pellets under its roost. (Owl pellets are the remains of animals that the owl ate — whole or in really big chunks. The pellet is the regurgitated remains of the owl’s meal, after the flesh and guts have been digested.)

Here’s what I found:

Great Horned Owl pellet, Columbus Park, Chicago, December 16, 2009.

The owl pellets are the fuzzy-looking gray things on top of the leaves. The gray fuzz is fur from whatever the owl ate. The white and yellowish bits embedded in the fur are bones from prey animals.

The more I looked, the more I found:

Great Horned Owl pellet, Columbus Park, Chicago, December 16, 2009.

This pellet -- about two inches across -- had more and bigger bones. When I picked it up, I saw ice crystals among the fur. When the owl spit out the pellet, it was still wet with stomach fluids. After the moist pellet hit the leaves, it froze solid.

The last pellet I found was the biggest and the boniest:

Great Horned Owl pellet, Columbus Park, Chicago, December 16, 2009.

The longest bone in this pellet is about two and a third inches long. It's a humerus, the upper bone from a front leg. I'm guessing it came from an animal bigger than a squirrel, maybe a rabbit or a small opossum or raccoon.

I saw one rodent or rabbit front tooth in a pellet, but the rest of the visible bones were from legs, feet, hips, shoulders, or backs.  I’m not good at identifying animals from their limb bones — I need to see teeth.

I guess we’ll go back at some point and dissect some of the pellets. If we find some jaws or skulls, we’ll know better what our urban owl was eating in Columbus Park.

Then we’ll wash our hands really well. After all, we’ll be handling owl vomit!

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We found more owl pellets on January 31st, including one containing a rabbit jaw. You can see them here.

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Here are links to information and activities about owl pellets: