Monday, June 11, 2012

Collecting & Dissecting Owl Vomit (Pellets)

You may recall, we have the wonderful pleasure of providing the home for a family of Eastern Screech Owls. My first post on this topic introduces the family in a proper manner. As for now, I want talk about their vomit! No really! As a high school teacher, I only knew owl pellets as something that I could buy from a biological supply company, varying in price from $2-$6, depending on the size of the owl. Make sure you see the "Dirty Jobs: Owl Vomit Collector" that I posted in my first post about our owl family.

So you can only imagine the excitement I felt the moment I realized that I could collect my own pellets. I knew nothing about doing this, I just started looking below the branches where I know they perch, and voila! I'll admit they are a a bit more wet then what I was used to seeing, but talk about fresh! 

For those of you who are wondering....why on earth would you collect owl vomit, or what on earth can you learn from owl we go. 

Owls eat small animals and insects. They eat their entire meal, feathers/fur, exoskeleton and all. However, they cannot digest the bones or the feathers/fur, so these are regurgitated 12 hours after they've eaten. So in this little morsel is a story of what the owl has eaten. Make this lesson about food chain/web or about primary, secondary, & tertiary consumers!  Make it a lesson in skeletal anatomy or play CSI detective. Its up to you how you want to approach it!  

The best way to go about dissecting owl pellets with students is for them NOT to know what they are. Because my son helped collect them, this wasn't really an option. But if possible, play the activity up a bit. Allow the kids to play detective.  Don't tell them where the pellets come from - have them use evidence to come up with explanations. 

Have students make observations of the whole pellet first. They can draw it, weigh it, and write this all down in their science lab notebook. Have them make predictions about what it is... what do they think it is made up? Tell them they are going to be able to dissect it, and then have the discovery tell a story. 

Then have them dissect it. Have the following materials on hand:
  • latex gloves (do as I say, not as I do!)
  • small paint brushes
  • forceps (tweezers) -- you can see we just used a fork
  • water: we tried soaking the bones, but it didn't really work.
  • science lab notebook
  • digital camera (optional)
  • small jar to store the bones they collect
As your students start to uncover the bones, have them separate the bones from the hair. Why would a skull be in this pelletWhat does that mean? Many kids think it is poop... so play along, and continue to ask them why they think so.  Ask them if they have seen bird poop before? on a car windshield? Does it look like that? 

Encourage them to talk out-lout about the pellets. You can do this by not answering their previous  questions, instead, asking them asking more questions! 

Possible interaction during the dissection: 
  • Student 
    • "Whoa! Look at this bone! What kind of animal is this from?"
  • What you might say, but should refrain, 
    • "Cool, huh? That's from a bird!"
  • What you should say instead, 
    • "Cool, do you have other bones that could help us figure out what animal that is from?" 

Then, depending on the age and interest of your students, have them determine what sort of animals the owl has eaten; rodent, shrew, mole, or bird. If you have time, have students can reconstruct the skeletons of the victims by glueing the bones together on a card. There are plenty of charts like this available for your use. 

Student should then be able to extrapolate something about the ecosystem of the owl. Where does it fit in a food web?  

As always, find out what new questions your students have from doing this activity! As I always say, "The more you know, the more you know you don't know!"

I wanted to mention that I got much of the information for this post from wonderful NSTA listserve individuals. A special thanks go out to Elizabeth Peterson and Alan Ascher who both provided great ideas on making owl pellet dissection inquiry instead of solely a dissection. Thank-you!   


  1. I LOVE this lesson! I'm hoping that my youngest will be willing this coming year (the oldest two wouldn't touch the pellets and I was so disappointed)!

    1. I know, its so interesting to know which things seem "yucky" to our kids, and which things are "cool!" Such a fine line, and not predictable. I thought my son would love making pinatas last Christmas, but he didn't like the feel of the flour/water paste! Really? Oh well.

      Any chance you can NOT share what it is, and see whether he can come up with its identity? Even so, maybe you could just do it by yourself, and see who ends up being interested!


  2. I noti ed that your son was not wearing gloves! I would think that wearing them would be a good thing--especially since the pellets had not been sanitized. It is a great activity for students of all ages to perform.


    1. George, thanks for that reminder. I was aware of the absence of gloves when we were doing it, but we weren't working on it long, and then we went in and have our hands and arms a good washing, with hot water and soap.

      Before bringing these into my classroom, I will be sterilizing them in the oven @ 250 for 15 minutes. That should do the trick!



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