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Thursday, March 17, 2011

Owl Pellet Study at Ostrander Elementary School

I completed the final owl study class with 2nd graders at Ostrander Elementary School in Wallkill, NY today. Here are the results of the owl pellet dissections.

Dutka’s class – 8 pellets dissected, prey found – 22 mice, 3 shrew, 0 moles, 1 bird

Lupoli’s class – 8 pellets dissected, prey found – 17 mice, 3 shrew, 1 mole, 1 bird

Nisa’s class – 5 pellets dissected, prey found – 7 mice, 3 shrew, 2 moles, 0 birds

Busse’s class – 8 pellets dissected prey found – 15 mice, 2 shrew, 0 moles, 0 birds

I had presented the following hypothesis to the students in response to the question what is the favorite food of Barn Owls. Mice and other rodents are the most favored food. Shrews, small insectivore mammals are the second favored food. Moles, another small insect and worm eating mammal, and birds, small birds mostly found in barn areas are tied for the third most favored food. What does the data tell us about the hypothesis?

In the 29 pellets dissected there were 77 prey animals found. Of these 77 animals 61 were mice. Mice were definitely the most favored food.

My hypothesis stated that shrews were the second favorite. Is that correct? Of the remaining 16 animals eaten by Barn Owls that produced the pellets we dissected 11 were shrews. What do you think?

Now look at the number of moles and the number of birds eaten, 3 and 2. Though it is not an exact tie, you can’t get any closer to a tie than that. It does seem that moles and birds are tied as the third favorite food.

Finally consider this. There are many other potential prey for the owls, small amphibians, large insects, other small mammals, but it seems from what we found that owls seem to not prey on them. You can research this to find out if Barn Owls might eat other animals. One research source is my blog, www.schoolyardnaturalist.blogspot.com. Check it and see what other data has been collected with owl pellet studies at other schools, including what was found at Ostrander in previous years.

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