The Arizona STEM Acceleration Project

Owl Pellet Dissection

Owl Pellet Dissection

3rd-5th grade STEM lesson

Allison Fournier

4/12/23

Notes for teachers

Dry Dissection

1. Unwrap the foil from the pellet.
2. Gently pull the pellet into two halves.
3. Use tweezers to pull apart the soft material surrounding the skull and bones.
4. Place bones into a separate pile on paper towel.
5. Discard the fur and other soft material.

List of Materials

• owl pellets (1 per pair of students)
• tweezers
• hand lens
• paper towel
• card stock
• tape
• marker for labeling
• gloves
• Dichotomous Key
• Owl Pellet Dissection Procedure

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Standards

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4.L4U1.11 Analyze and interpret environmental data to demonstrate that species either adapt and survive or go extinct over time.

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5.L4U3.12 Construct an argument base on evidence that inherited characteristics can be affected by behavior and/or environmental conditions.

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Objective(s):

1. Analyze and interpret data they have collected from an owl pellet dissection to answer a question.
2. Use a dichotomous key to identify bones of prey species found in an owl pellet.

Agenda

1. Make copies of the Owl Pellet Dissection Procedure and Dichotomous Key.
2. Gather materials and set up students’ workstations.
3. Complete dissection and identification.
4. Tape to cardstock.

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Driving Question

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What animals did your barn owl eat this week?

Observe the bones it swallowed to identify its prey!

Hands-on Activity Instructions

1. Students spend 5 minutes observing the pellets without touching them. Use starters “I notice” and “I wonder” on the Owl Pellet Dissection worksheet to record their observations.
2. Discuss how Owl Pellets are formed. (They are regurgitated material that cannot be digested, not poop.)
3. Discuss basic information about Barn Owls. (Hunt in open areas like fields and eat a variety of small animals, depending on what they can catch.)
4. Examining the contents of a pellet provides a good record of what the owl has eaten recently. Tell students they will be collecting data and using a Dichotomous Key to determine the species that are found in the pellets.

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Dissection

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1. Students will dissect the owl pellets then use the Dichotomous Key to identify the bones of the species in the pellet.
2. Review the steps of the Dissection Procedure. (Post on the board.)
3. Give students gloves. Remind them to wash their hands when they have finished.
4. Give students 30 minutes to dissect their pellets.

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Dichotomous Key

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1.Students will use the Dichotomous Key to identify the skulls of the species in their pellet.

2.Discuss vocabulary students may encounter. (skull, cranium, mandible, molar, incisor, canine, and root)

3.For each skull that they find, have them use the key to identify it. Record the total number of skulls for each species they find.

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When finished, students can use the cardstock to tape and label their bones.

Assessment

Discuss their findings and determine which species was most predominant.

Make a class graph of the findings.

Differentiation

Some students might need help with the identification.

Remediation

Extension/Enrichment

Compile a class data set.

Calculate the fraction and percentage of barn owl diet for each species.

Create a bar graph displaying these percentages.