owl pellet dissection lab hypothesis

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Resources for the Trail and Classroom®

Owls & Owl Pellet Dissection Resource Guide

This guide provides 40 pages of full-color, comprehensive instruction on owl pellet dissection and prey identification. It features self -directed readings, easy-to-follow illustrated explanations, guiding questions, inquiry-based activities, a lab investigation, key vocabulary review, and assessment review questions along with a post-test. This manual covers the following topics: owls as birds of prey, the barn owl, owl food webs, all about pellets, rodent identification, vole identification, mole identification, shrew identification, bird identification, dissecting owl pellets lab investigation, and NGSS correlations. Recommended for teachers of students in grades 4 through 9.

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Teaching AP® Science

Resources By Kristi Schertz

Owl Pellet Dissection-Trophic Levels and Energy Loss

Owl pellet dissection is used to teach ecology topics such as food webs, biomass pyramids and energy loss.

Buying Pellets and Materials.

Both small and large pellets work with this lab. I’ve used small when my funds are more limited and large when they’re not. Large pellets give more prey per pellet which is fun for the kids.  If you don’t have enough science funds, here’s some suggestions on where to find additional money for your science classroom.

I buy one pellet per team of 4 students due to cost. This is not ideal, but they are only dissecting to count the prey–not to identify all the bones or do anything else with them.

The pellets are sterilized, but I provide gloves for kids who prefer gloves. My pictures show dissection trays, but they’re not necessary. A paper plate or a paper towel works just as well.

Since I try to teach inquiry-style with the 5E learning cycle, I don’t want to pre-load information into the kids’ brains. I do, however, want them to see where owl pellets come from and basic dissecting techniques. I assign these videos the night before on Edpuzzle, but these can also be shown in class prior to the lab.

Phenomena-based video of baby owl regurgitating a pellet.

Basic information and dissection techniques.

Dissecting pellets

There are many variations of the owl pellet lab which are wonderful.   My copy is a 5E learning cycle which was adapted from the original creator, Dr. Ewoldsen.

Kids can use their fingers or tweezers to take the pellet apart. Provide reference sheets. Many can be found for free online.

I altered this reference sheet to help kids correctly identify a mouse vs. a rat. I make kids measure as they don’t readily know how large 1 cm is.

I combine ecocolumn data along with owl pellets at the same time so 4 kids have more tasks to do. Two kids take ecocolumn data while the other 2 kids in the group dissect the pellet.

After about 20 minutes both pairs are finish and all 4 of them will do calculations and answer questions on their owl pellet papers together.

Calculations and Analysis Questions

(I want to give a shout-out to the original creator of this lab–the famous Dr. E)

Students take their data and fill in a chart. The entire chart is NOT filled in.  Most of the prey will be a rat or mouse. Students always think they found something else like a mole or shrew, because it sounds more interesting, but unless they can ID a skull, it  probably isn’t. (I have some kids who think they have a shrew, because the ribs they find are so skinny….)

Next, the students create a numbers pyramid and a food web. I draw a pic on the lab white board to help them.

For the food web, you can choose to have students create a food web from just the prey found in their pellet or from all the prey the owl could eat.  I choose the first option (but am thinking of switching to the second for next year to give them more practice with a more complicated food web).

Next comes a biomass pyramid which is the crux of this lab in terms of calculating energy loss.  Students need to complete the biomass chart and then draw a pyramid. I have detailed instructions on the lab paper on how to do that since it confuses them.  

Working in groups for the questions is helpful so they can hash out what the correct answers should be and learn better. I flipped my class last year so I have the luxury of time to allow an extra day to do this.  Students are often confused that the energy “loss” from the prey to the owl is over 99%. They need to understand that 90% energy “loss” is an average and they will hypothesize why the loss is this lab is so much higher (the owl doesn’t weigh very much for being a top predator).  Its good for them to question their numbers, however, if they seem “off” as that is a good skill for the math is this course.  But, in this case, its correct.

The questions also discuss that energy is not really “lost”, but becomes heat and an unusable form for food in ecosystems–1st and 2nd laws of thermodynamics.

Normally, I have the kids write a conclusion and submit through Turnitin.com, but this year, I had them do an oral conclusion on Flipgrid. The results were much stronger in terms of understanding energy loss than if they did the conclusions by themselves.   Much of the AP® Exam is higher level thinking and students can help build these skills by working together.

Kristi Schertz

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Owl Pellet Dissection

Biology - high school, virtual lab.

1. Owl Pellet Dissection

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Owl Pellet Dissection

Image credit: Charles Welch

What animals did your barn owl eat this week? Observe the bones it swallowed to identify its prey!

Students will be able to:

• analyze and interpret data they have collected from an owl pellet dissection to answer a question.
• use a dichotomous key to identify bones of prey species found in an owl pellet.
• Many pellets that are sold for student use have been heat sterilized to kill bacteria, making them safe to handle with bare hands. Even so, students should wash their hands with soap and clean their work area thoroughly after the dissection. Pellets should not be dissected in areas where food is prepared or consumed.
• tweezers (1 per student)
• hand lens (1 per student)
• napkin or paper towel (1 per student)
• (optional) editable Powerpoint Deck with imagery
• There are two versions of the key: a visual, branching version and a text version. Use whichever version you feel your students will be more comfortable with.
• What Do Owls Eat? worksheet (1 per student)
• Owl Pellet Dissection Procedure worksheet (1 per student)

Optional materials to create a miniature collections tray for one's findings:

• large petri dish (1 per student)
• cotton balls (2-3 per student)
• Sharpie for labeling petri dishes
• scotch tape
• canines: the long, pointed teeth next to the incisors; general used for piercing and tearing
• incisors: the front-most teeth in the jaw; generally used for nibbling
• molars: the backmost teeth in the jaw; generally used by humans or rodents for grinding, or for crushing by insectivores.
• premolars: the teeth located between the canines and molars
• root: the part of the tooth that is anchored in the jaw bone
• cranium: the part of the skull that surrounds and protects the brain
• diastema: the large space between the incisors and molars; found only in herbivores
• mandible: the lower jaw
• skull: the structure that includes both the cranium and the mandible together
• dichotomous key: a tool to help one identify things in the natural world – such as trees, wildflowers, and mammals – by a series of choices between two items. Pronounced “dye-KAH-tah-mus.”
• Make one copy of the What Do Owls Eat? and  Owl Dissection Procedure worksheets for each student .  
• Gather materials and set up students’ workstations with materials for the dissection.  
• Decide which dissection procedure you would like students to perform. There are two procedures that can be used to dissect an owl pellet; dry or wet dissection:

Dry dissection

• Unwrap the foil from the owl pellet.
• Gently pull the pellet into two halves.
• Use tweezers to pull apart the soft material surrounding the skull and bones.
• Place bones into a separate pile.
• Discard the fur and other soft material.

Wet dissection

• Place the owl pellet in a petri dish filled with water. Soak pellet for 10 minutes.
• Leave your pellet in the dish and gently pull the pellet into two halves.
• Use tweezers to pull apart the soft material surrounding the skull and bones. You can soak larger bones in the petri dish to help loosen the material that is packed around the bones.
• Discard water and petri dish.

Part 1: I notice, I wonder…

• Pass out owl pellets to each student or pair of students.  

NGSS Connection: This portion of the lesson connects to the Practice of Asking Questions because students generate their own questions about owl pellets through firsthand observations using the “I notice, I wonder” sentence starters. Questions that are generated from student’s firsthand observations help them to develop their own ideas and explanations for phenomena in the natural world. Students’ questions can be recorded on the Owl Pellets Dissection worksheet. Students can also select one of their questions to try and answer with throughout the course of their dissection.  

Educator Tip:  Be sure to address the misconception that owl pellets are poop. Owl pellets are regurgitated material that cannot be digested.  

• Discuss basic information about barn owls. Explain that barn owls hunt in open areas like fields and eat a variety of small animals, depending on what they can catch. You may download and edit this Powerpoint deck , if you'd like.  
• Go over the common prey species of barn owls in the Pacific Northwest and Northern California.  
• Explain that examining the contents of a pellet provides a good record of what the owl has eaten recently. Tell students that they will be collecting data and using a dichotomous key to determine the prey species that are found in the owl pellets.

Part 2: Dissection

• Inform students that they will first dissect their owl pellets, and then they will use a dichotomous key to identify the bones of the prey species found in the pellet.  
• Go over the steps of the dissection procedure, following the steps outlined in the Owl Pellets Dissection worksheet . Make sure students understand what they will be doing at each point.  
• Inform students that these pellets have been heat-treated to sterilize them. However, to be on the safe side, they will have to wash their hands and clean their work area after the dissection. They should not eat, drink, or put their hands in their mouths during the activity.  

Educator Tip:   Student’s excitement over the first bones that are uncovered can lead to distraction from the dissection. Encourage students to stay organized, follow the procedure, and keep careful track of what they find.  

Educator Tip: During the time that students are dissecting their owl pellets, you can draw the class data table and “Percentage of Prey Species Found in Owl Pellets” graph from the What do owls eat? worksheet on the board.

Part 3: Dichotomous key

• Tell students that they have collected the data of what owls eat by dissecting their owl pellets; now they need to analyze their data. To do this, students will need to identify the skulls of the prey species in their owl pellets using a dichotomous key.  
• Go over what a dichotomous key is (a tool to help one identify things in the natural world – such as trees, wildflowers, and mammals – by a series of choices between two items). The key works through a series of questions, each with two possible answers. Each answer leads to a new question until the identification is reached.  
• Before handing out the dichotomous key, go over the vocabulary that students will encounter in the key related to identifying the skulls (e.g.; skull, cranium, mandible, diastema, molar, incisor, canine, and root).  
• For each skull that the students find, have them use the dichotomous key to identify it. Explain that each student should record the total number of skulls of each prey species they find on their What do owls eat? worksheet.  
• Tell students to start at STEP 1 on the key.  
• Once each student has identified and counted the total number of each prey species found in their pellet, compile a class data set. Have students come up to the board and put tally marks in the box next to the prey specie(s) that they found inside their pellet.  
• Calculate the fraction and percentage of barn owl diet for each prey species. A bar graph displaying these percentages can be filled in on the What do owls eat? worksheet.  

NGSS Connection: This portion of the lesson connects to the Practice of Analyzing and Interpreting Data because students must draw conclusions from their analysis of the data table and bar graph to determine which of the prey species was eaten the most by the owls. Based on their calculations of fractions and percentages, students should be able to determine the answer to the scientific question, “Which prey species was eaten the most by the owls?”  

NGSS Connection: This portion of the lesson connects to the Crosscutting Concept of Patterns because students are asked to identify patterns in the data to make a prediction about the owl’s environment. For example, if your class data shows that 90% of the prey species found in the owl pellets were voles, then you can predict that voles were the most abundant prey species in the environment.

Part 4: Display owl pellet bones in a petri dish (optional)

• Instruct students to write their names on the lid of the Petri dish with a Sharpie. This container will store the skulls and bones from their owl pellet.  
• Have students spread out a layer of cotton ball padding on the bottom of the petri dish and place the clean skulls and bones from their pellet onto this soft layer.  
• Close the lid of the Petri dish and tape it closed with Scotch tape.

Discuss with the students:

• Did each student find the same prey species in their pellet? Why or why not? Owls eat a mixed diet depending on what is available, so different owls will probably have eaten different things.  
• What is a dichotomous key? How does it help you learn more about organisms? A dichotomous key is a tool that helps you identify things in the natural world – such as trees, wildflowers, and mammals – by a series of choices between two items.
• Ask students to select one of their favorite questions from their “I wonder…” list on the Owl Pellets Dissection worksheet to investigate.  

NGSS Connection: This portion of the lesson connects to the Crosscutting Concept of Structure and Function because students are asked to observe the shape and size of the prey species’ teeth and think about how that is related to their function. For instance, the skulls of rodents, such as mice and voles, have front teeth that grow continuously. These front teeth help them to nibble the leafy vegetation that they eat. Moles and shrews will have differently shaped teeth because they have a different diet.  

• Challenge students to design their own dichotomous key to classify everyday items. Items that could be classified include student’s shoes or different types of candy. The beginning of a candy dichotomous key for classifying types of candy might look like this:

1. Candy is chocolate.                     Go to 2.     Candy is not chocolate.                  Go to 3.

2. Candy is rectangle-shaped.          Hershey’s bar.     Candy is circular-shaped                 Go to 4.

Owl Pellets

Owls swallow their prey whole, therefore in addition to the meat that they digest for food, they swallow other material such as bones, fur, or feathers. Owls are unable to digest these materials, so they are regurgitated in a compacted mass. This compacted mass of fur, bones, and any other indigestible material is called an owl pellet. Despite what it looks like, pellets are not owl poop (which is what many students assume). Owl pellets are more like owl puke.

Most owls produce about two pellets each day. A pile of pellets can often be found below an owl’s roosting site. The bones of prey that are found within an owl pellet can be identified with the help of a dichotomous keys or bone-sorting charts. Studies with captive owls have shown that pellets give an almost perfect record of what the bird has actually eaten. The contents of owl pellets provide a fascinating window into the life of a barn owl. In fact, fossilized pellets have been used to study the diet of ancient owls.

The pellets provided with this kit are collected from common barn owls ( Tyto alba ). Barn owls are the most widespread species of owl and one of the most widely distributed vertebrate species on the planet. They are found on every continent except for Antarctica.

Barn owls hunt in open areas, such as fields, marshes, and grasslands. They are mainly nocturnal and depend on their remarkable sense of hearing to hunt. Their hearing is so accurate that they are able to capture prey in complete darkness. Barn owls nest in enclosed spaces, such as small caves or holes in trees. Human-built structures, including barns, also provide comfortable nesting spaces. Human activities, such as clearing forests for farmland, have extended the open areas in which barn owls can hunt.

Barn Owl prey species

While some predators prefer to eat a specific type of prey, others are less picky and will eat whatever is readily available. Barn owls eat a mixed diet of whatever small critters they can catch in their fields. They feed mainly on the small land mammals that live the fields where they hunt. They will also eat small birds, bats, and occasionally small reptiles. As a result, the barn owl diet varies regionally depending on what prey animals are common in the area. For example, owl pellets from Northwestern United States most frequently contain the remains of voles, which are abundant in the area. On the other hand, voles are absent from parts of the Southeast; in those areas, rats are more commonly found in owl pellets.

The pellets provided with this kit are collected in the Pacific Northwest and Northern California. Common prey of barn owls in this region include the following:

Rodents are mammals that have front teeth that grow continuously. 40% of all mammal species are rodents.

• Deer mice: Deer mice feed on seeds, nuts, fruit, and leafy vegetation. They have large round ears, long furless tails, and brown fur with lighter fur on their undersides.  
• Voles: At first glance, voles can be easily confused with mice. They are similar in size and color, but voles have a stouter body than mice, smaller eyes and ears, and short furry tails. Voles eat stems, leaves, seeds, fruit, roots, and flowers.  
• Pocket gophers: These are burrowing rodents that eat roots and tubers. Pocket gophers use their fur-lined cheek pouches to carry food into their tunnels for storage.

OTHER MAMMALS

These animals are not rodents because they lack the characteristic of continuously growing incisors. Moles and shrews belong to a group of mammals called insectivores. Bats belong to their own group and are the only mammals capable of true flight. Other mammals commonly eaten by barn owls include:

• Moles: Moles have strong front feet and large claws that they use to burrow in search of earthworms, insects, and other small invertebrates. Moles have very poor vision, but have excellent hearing and use small hairs on their feet and tails to help sense their surroundings.  
• Shrews: Shrews are some of the smallest living mammals. They have small eyes, hidden ears, and pointy snouts. Shrews eat insects, worms, snails, and spiders, and dig narrow burrows. Although they look similar to mice, shrews are more closely related to moles and hedgehogs.  
• Bats: Smaller bats are sometimes eaten by barn owls. These nocturnal flying mammals are not surprising prey choices since they tend to be out hunting at the same time as owls are.

While mammals are the consistent staple of a barn owl’s diet, small birds are an important alternative during the winter, when mammals tend to be less active and more difficult to find. Bird bones are thin and delicate; as a result they may be partially digested by barn owls, making them more difficult to find in the pellets.

Science and Engineering Practices

Asking questions

K-2: Ask questions based on observations to find more information about the natural and/or designed world(s). Ask and/or identify questions that can be answered by an investigation.

3-5: Ask questions that can be investigated and predict reasonable outcomes based on patterns such as cause and effect relationships.

Analyzing and interpreting data

K-2: Use observations (firsthand or from media) to describe patterns and/or relationships in the natural and designed world(s) in order to answer scientific questions and solve problems.

3-5: Represent data in tables and/or various graphical displays (bar graphs, pictographs and/or pie charts) to reveal patterns that indicate relationships. Analyze and interpret data to make sense of phenomena, using logical reasoning, mathematics, and/or computation. Compare and contrast data collected by different groups in order to discuss similarities and differences in their findings.

6-8: Construct, analyze, and/or interpret graphical displays of data and/or large data sets to identify linear and nonlinear relationships. Analyze and interpret data to provide evidence for phenomena.

Disciplinary Core Ideas

K-LS1-C: Organization for Matter and Energy Flow in Organisms

• All animals need food in order to live and grow. They obtain their food from plants or from other animals.

4-LS1-A: Structure and function

• Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior, and reproduction.

Crosscutting Concepts

K-2: Children recognize that patterns in the natural and human designed world can be observed, used to describe phenomena, and used as evidence.

3-5: Students use patterns to make predictions.

6-8: Students use patterns to identify cause and effect relationships, and use graphs and charts to identify patterns in data.

Structure and function

K-2: Students observe the shape and stability of structures of natural and designed objects are related to their function(s).

3-5: Students learn different materials have different substructures, which can sometimes be observed; and substructures have shapes and parts that serve functions.

Related Performance Expectations

Remember, performance expectations are not a set of instructional or assessment tasks. They are statements of what students should be able to do after instruction. This activity or unit is just one of many that could help prepare your students to perform the following hypothetical tasks that demonstrate their understanding:

MS-LS2-2:  Construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems.

Martin, Jason M., Richard N. Raid, and Lyn C. Branch. (2005) Barn Owl ( Tyto alba ). Retrieved September 25, 2008 from University of Florida IFAS Extension website: http://edis.ifas.ufl.edu/UW216 

Sparks, John and Tony Soper. (1970) Owls: Their natural and unnatural history . New York: Taplinger Publishing Company.

Taylor, Iain. Barn owls: Predator-prey relationships and conservation . Cambridge: Cambridge University Press.

Tyler, Hamilton and Don Philips. (1978) Owls by day and night. Happy Camp, CA: Naturegraph.

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Science Projects > Life Science Projects > Modeling Ecosystem Food Webs with Owl Pellet Dissection  

Modeling Ecosystem Food Webs with Owl Pellet Dissection

Grade Range:  Adaptable for Grades 3 – 8.

Overview:  Learn about food webs by dissecting owl pellets.

What You Need:  Owl Pellet Dissection Kit

Activity Objective:  Draw and understand a food web based on what is observed in an owl pellet.

Safety Precautions:  Owl pellets have been heat-sterilized, yet it is still a good idea to protect your hands and surfaces! Cover students’ workspace with newspaper, foil or use a disposable tray. Wear disposable gloves and wash hands thoroughly after handling owl pellets.

How does a predator-prey ecosystem, where one member is routinely eaten for food, continue to exist?

Download: Owl Pellet Dissection Lab

Introduction

A food chain is a hierarchy of organisms that rely on each lower member of the chain for food.  Often drawn as a simple diagram with arrows from one organism to the next, food chains highlight the transfer of energy from one trophic level to the next. A trophic level refers to the position an organism occupies in a food chain. Food chains start with plants (primary producers) which obtain 100% of their energy from the sun. Plants and subsequent members of the food chain are then eaten for food by consumers. However, as little as 10% of the energy in each level of the food chain can be transferred to the next. This means that the size (which impacts the amount of available energy) of a lower trophic level dictates the size of the next trophic level.

• Primary Producers (Autotrophs) – use energy from the sun
• Primary consumers – eat primary producers
• Secondary consumers – eat herbivores
• Tertiary consumers – eat other carnivores
• Quaternary consumers – eat other carnivores

A predator-prey ecosystem can be thought of as a subset of a larger food chain in which one consumer (predator) feeds off a lower consumer (prey). These types of relationships are very common in nature and provide an interesting way to study ecosystem population dynamics, or how the number of predator and prey are related.

What do you know about food chains and how the size of each trophic level or position in the chain is  determined?

What To Do Part 1

1. Use the owl pellet kit’s supporting materials to first dissect the owl pellet.

2. Can you identify different bones? Use the bone sorting chart and identification key.

3. Try to fit the bones together. Can you determine what the owl ate?

What To Do Part 2

1. Based on your observation, record the number of each of the animals that your owl ate:

2. What other types of bone did you find?

3. What other undigested material, if any, did you find?

4. Assume for every day the owl eats it regurgitates 1 pellet per day, on average. How many animals would an owl then eat:

In a month:

5. Draw a food chain, with an owl at the top. Label the chain (primary producer, etc.). Add in other organisms that would make this a food web rather than a food chain.

6. Assuming 10% of energy is transferred from one trophic level to the next, what percentage of the initial (plant) energy does the owl receive?

7. What would happen if an animal in this food web did not exist?

8. Now that you’ve finished the activity, complete the below table to answer the guiding question.

i. Add the relevant data you collected and calculations to the Evidence section

ii. Interpret and analyze the data to determine what it means

iii. Add your justification and assumptions to the Justification section

iv. Based on analysis and interpretation of the evidence, develop your Claim

v. Present and discuss your claim

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Owl Pellet Dissection

​All of those are valid questions to consider. I love doing the lab because owl pellets are relatively affordable (especially if you put students in groups of 2 or 3), and engagement is high. Here are some ideas on how to up the rigor with high school students:

1. COMPARE PREY SPECIES-   Depending on your budget, order both northwest and southwest pellets. You can have half the students dissect northwest pellets and the other have dissect southwest pellets. Compare the prey that are found and discuss the differences. Other birds of prey create pellets too- what would students expect to find in a heron or hawk pellet? 

2. TROPHIC PYRAMIDS- After dissecting the pellets, have students turn the data into trophic pyramids. Students can create a pyramid of numbers using class data- f or every owl (number of pellets you passed out), how many prey were found? They can also create a pyramid of biomass if you give them numbers to work with. Suppose an average barn owl has a mass of 500g and an average mouse has a mass of 20g. If one owl eats one mouse per day, what would a pyramid of biomass look like for 1 year? Have them work the math and draw it out. 

​3. ENERGY TRANSFER- Discuss energy transfer from prey to predator. You could give students hypothetical numbers (in joules or kcal) and have them calculate the percentage of energy transferred from one trophic level to the next. You’ll want it to work out to around 10%.

4. SKELETON ASSEMBLY- If time allows, have students take their bones and re-assemble the prey skeleton. You can easily google an image of a mouse skeleton and have students glue on as many bones as they can identify. 

Looking for a lab worksheet for an owl pellet dissection? Click here ! I also have a blog post with more food chain and web activities you might want to check out. 

Let me know if you have any questions! Rock on!

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FREE Owl Pellet Dissection Guide

Owl pellet lab.

Not sure how to start your Owl Pellet Dissection Lab or just need a refresher? Start here and use this  FREE Owl Pellet Dissection Guide to help you. For a printable version of this guide, click the button below.

What Is An Owl Pellet? A Very Brief Explanation.

After swallowing its food whole the Barn Owl relies on its Gizzard to help it digest. After swallowing  bones, fur, and all, the Gizzard separates out what the Owl cannot digest. Several hours later, after the Gizzard has finished its job, the Owl regurgitates a Pellet or sometimes more than one. This pellet is a mass of all the indigestible bits that the gizzard separated.

At Oregon Owl Pellets our Owl Pellets come from Oregon Barn Owls , we gather the pellets from our local area barns and other structures Barn Owls like to nest in.

Planning the Owl Pellet Dissection Lesson

Supplies and materials.

The following will list some, but not all supplies you may need.

• The most important part of your Owl Pellet Dissection Lab.
• You may need a larger one, depending on the size of the pellets.
• For tearing apart pellets and pulling out bones.
• Note: A small amount of water can be used to soften the pellets prior to students opening them. This makes them easier to dissect and reduces the risk of breaking remains while opening the pellets.
• A good reassurance for those who might be a little squeamish.
• *Facemask (Optional)
• Owl Pellet Bone and Dissection Chart helps students identify bones found in owl pellets .
• Like any lab, have adequate space for your students to work.

*Included in our Owl Pellet Dissection Kits .

Things to keep in mind.

Rodent bones are the most common bone found in owl pellets . These can include voles, rats, mice, and even shrews. To avoid breaking fragile bones, students should work slowly. This is when using water to soften the owl pellet can be very important. Put a little on each pellet.

" Remind your students not to put the Owl Pellet in their mouth. If they do, don’t worry, the sanitized pellets will not hurt them. However it would be a good precaution to have them rinse their mouth with mouthwash afterwards. "

Dissection and Bone Collection

As your students begin dissecting the pellets, have them set aside bones or other remains they find. Sometimes this can include rodent skulls.

Encourage them to identify what they find. For older students this may be easier so give them the added challenge of putting bones from the same animal together.

We provide a free bone chart with the purchase of our Owl Pellets ! Or click the button below to download a FREE PDF of our Owl Pellet Bone Identification Chart and print as many copies as you need!

Highest Quality And Safety

We carefully hand select each Owl Pellet to ensure quality. Heat thoroughly to kill any harmful bacteria, protecting you and your students. Then finally, wrap each pellet to protect it during shipping. In short, we want you to receive only the best quality Owl Pellets for your classroom.

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Owls & Owl Pellet Dissection Resource Guide with Online Multimedia Lesson

• Item #: 455070

Description

Specifications.

• Detailed guide for owl pellet dissection
• Free online access to digital resources
• Virtual owl pellet dissection lab included

Product Details This 40-page, full-color guide is a comprehensive overview of owl pellet dissection and prey identification. It features self-directed readings, easy-to-follow illustrated explanations, guiding questions, inquiry-based activities, a lab investigation, key vocabulary review, assessment review questions, and a post-test. In addition, it also includes a code for 1-year access to complementary online lessons featuring an owl pellet dissection virtual lab, narrated tutorials, interactive exercises, quizzes, and more! This is the perfect resource for pre-lab prep or post-lab review when conducting actual hands-on labs, or use as a substitute for owl pellet dissection lessons. Soft cover.

• Owls—Birds of Prey
• The Barn Owl
• Owl Food Web
• All About Pellets
• Rodent Identification
• Vole Identification
• Mole Identification
• Shrew Identification
• Bird Identification
• Dissecting an Owl Pellet Lab Investigation
• Energy Flow
• Food Chains
• Energy Pyramid
• Food Web Balance

Note: Online lesson code provides access to all of your students for 1 year from time of activation.

• 1 Guide
• 1 Online Lessons Code (1-year access from date of activation)

If for any reason you are not satisfied with this item, it is eligible for a return, exchange, refund, or credit up to 180 days from date of purchase. Restrictions may apply. Returns & Exchanges Policy.

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Owl Pellet Dissection

INTRODUCTION : In this activity, you will learn about owls, predator/prey relationships, the use of dichotomous keys, animal adaptations (i.e. behavioral and physical), and information regarding owl habitats. You will spend time dissecting and examining the contents of an owl pellet.

CONCEPTS : (1) Owls have acquired physical and behavioral adaptations to be successful in their environments. (2) Dissecting owl pellets provides information about owls’ habits and their role in nature.

OWL ADAPTATIONS: Owls are a type of carnivorous bird called raptors. Other raptors include hawks, eagles, falcons, and ospreys. Most raptors hunt small mammals, birds, amphibians, reptiles, and larger invertebrates. All raptors possess similar adaptations that allow them to hunt: they are strong and agile fliers; they have keen eyesight to locate prey, strong legs and talons for capturing prey, and hooked bills to tear flesh. Although owls share these characteristics, they have adapted to their nocturnal lifestyle. Other species of raptors are active primarily during the day so they have not evolved these specialized adaptations to be active at night.

OWL ADAPTATIONS: Owls are a type of carnivorous bird called raptors. Other raptors include hawks, eagles, falcons, and ospreys. Most raptors hunt small mammals, birds, amphibians, reptiles, and larger invertebrates. All raptors possess similar adaptations that allow them to hunt: they are strong and agile fliers; they have keen eyesight to locate prey, strong legs and talons for capturing prey, and hooked bills to tear flesh. Although owls share these characteristics, they have adapted to their nocturnal lifestyle. Other species of raptors are active primarily during the day so they have not evolved these specialized adaptations to be active at night.  

(1) Eyesight: The size and structure of owls' eyes allow for amazing visual ability. Owls' eyes are so large that there is little room for muscles inside their eye sockets needed to move their eyes. To compensate, owls are able to turn their heads 270 degrees. Larger eyes allow for more light to enter the pupil, which is the round center of the eye. The owl "sees" when light contacts rod and cone cells at the back of the eye. Rod cells gather light and are needed when trying to see in low light conditions, but they do not distinguish color. Cone cells allow for color vision. Since most owls hunt at night, their eyes contain mostly rod cells; therefore, they can only see in black and white. Owls focus on prey with binocular (two-eyed) vision, which means that each eye sees an object from a slightly different angle. The two views overlap, triangulating the object in the owl’s sight, and allowing them to judge exact distance. Their sight is so focused that an owl could read a newspaper a mile away by the light of a candle (if it could only read). Although owls can see distant objects clearly, they cannot see close objects well. Owls will bob and turn their heads to change their viewpoint when focusing on close objects. This behavior makes near objects stand out from the background so they can judge the object’s location more accurately.  

(2) Hearing: Owls have large, oval-shaped ear openings bordered in the front with a fleshy, raised flap called an operculum. This is similar in function to a hand cupped over the front of a person’s ear to capture and amplify sounds from the rear. Many owls, such as the Barn Owl, have facial feathers shaped similar to a satellite dish that collect and direct even the lowest intensity sound waves down the ear channel into the ear. The unusual positioning of owls’ ears also allows them to locate sounds. One ear is higher and points slightly more forward than the other. This asymmetrical positioning of the ears produces a difference in the time that it takes for a sound to reach each ear. Owls can detect the exact distance and location of sounds by analyzing the time difference between sounds. For example, if a sound arrives to the higher ear first, the owl knows that it came from above. 

(3) Silent Flight: Not only can owls see and hear their prey, their prey cannot hear them coming. The owl has a lightweight body and a large wing area, which allows it to fly using a slow, controlled wing-beat. Soft, comb-like serrations on the wing feathers and frayed edges on the tips of the tail feathers break up the air flow and muffle sound, enabling nearly silent flight. Most other bird species have a smooth, knifelike edge on their wings, which creates noisy friction as they cut through the air. Many owl species also have feathers extending down their legs, which muffle sound during flight. Show the students the wing and the talon. Point out the serrated feather ends. 

(4) Talons and Beak: Talons are used for capturing and grasping prey. The toes of an owl extend to the sides to prevent small mammals from moving sideways and escaping. Many owl species have feathers extending down their legs, which insulate their feet during winter. A strong, sharp, curved beak allows owls to tear up prey if it is too large to swallow. Owls normally kill their prey by grasping it with their talons and then biting its neck.  

(5) Behavior: Most owl species will migrate if the winter is harsh enough, but they will continually return to the same area. Owls develop an intimate knowledge of their territory and hunting ground through their methodical behavior. They will use the same trees as lookout perches to search for and ambush prey. 

(6) Diet: Owls hunt small mammals, birds, and invertebrates like insects and worms, and most owls will swallow their prey whole. However, some owls have a varied diet. The Great Horned Owl eats rodents, pheasants, quail, small birds, fish, amphibians and reptiles.

DISSECTING OWL PELLETS : Examining owl pellets provides important information to ornithologists (i.e. those who study birds) regarding owl adaptations and habits. Scientists can determine what owls are eating at various times and places by finding and dissecting owl pellets. Owl pellets also provide information about the approximate numbers of prey animals in the owl's feeding area, which is valuable information to scientists studying animal populations. Pellets are often found at the base of a perching tree. Owls can digest only the soft muscles and organs of their prey. The bones, teeth, fur, feathers, scales, or insect skeletons are too dense and cannot be converted into energy.

 The harder parts may also puncture an owl's soft, curved intestines if passed through its digestive tract. Instead, the waste material is formed into a pellet by the gizzard muscles and passed back up the esophagus to be cast out (thrown up) about twelve hours later. Although other birds, like eagles and hawks, also regurgitate pellets, owls are more efficient at it and they regurgitate more frequently. Owls swallow their prey whole, ingesting the entire skeleton. Other raptors selectively tear at their prey, eating only the soft digestible parts and leaving the indigestible bones. Also, unlike other birds, owls do not have a crop, which is an organ that holds food until the stomach is ready to receive it. Other species of raptors do not need to regurgitate pellets as frequently as owls because some of the food remains in the crop, preventing food from passing up through the mouth for several hours. Although pellets are waste material, they provide food and shelter for other organisms. Pellets sometimes provide homes for clothes moths, carpet beetles, and fungi. You may find droppings, cocoons or exoskeletons from these animals in the pellets.

PROCEDURE : (1) Use a needle, tweezers or sticks to dissect an owl pellet. The pellets have been “scientifically sanitized” or autoclaved so they are free from bacteria and diseases. Nevertheless, wash your hands carefully after working with the pellets. (2) Carefully separate the bones from the soft material in the pellet. 

DATA COLLECTION : (1) Read about the Barn Owl and Introduction to Owl Pellets in the “Student Guide”. (2) Use the supplemental handouts and posters provided to assist you in sorting and skull identification of the prey as well as to identify as many bones and skulls as possible. (3) Examine each skull to determine if it has teeth. If there are no teeth, it is a bird skull. If teeth are present, read the statements on the key to determine which statement is more correct about the skull. (4) Once you have identified the bones and skulls, record the data and complete the questions that follow.

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Barn Owl pellet analysis

Owl pellet facts & video: Find out all about Barn Owl pellet dissection and how to analyse the contents.

What is a Barn Owl pellet?

(a 4-minute video with Head of Conservation, David Ramsden MBE)

What are Barn Owl pellets

• Where to find Barn Owl pellets

Owl pellet storage and preparation

Barn owl pellet dissection, barn owl pellet contents identification, barn owl pellet analysis and dissection for schools.

• Barn Owl Trust pellet dissection pack
• Barn Owls are unable to digest the fur and bones of their prey, which they usually swallow whole.
• The indigestible parts are regurgitated (cast up through the beak) in the form of an owl pellet.
• After feeding, producing a pellet takes 6 hours or more.
• After each night’s hunting an owl regurgitates 1 or 2 pellets.
• Barn Owl pellets are typically about the size of a man’s thumb and black when fresh.
• Pellets often contain the remains of 4 or 5 small mammals.
• Pellet dissection can tell you exactly what a Barn Owl has eaten.

Where to find Barn Owl pellets

Pellets often accumulate at roosting or nesting sites , where owls can hide away and shelter from the weather. Knowing the signs of occupation will help you find pellets and determine if they are from Barn Owls or not. Barn Owl pellets are black when fresh, turning grey as they get older.

Pellet identification chart : Identify the bird pellets you find. Most birds produce pellets, which look different according to what they eat. Or have you found something else entirely – like a fox scat for instance?

More about owl pellet identification on our Barn Owl Survey website .

When collecting pellets from a potential nest site, do take care. Barn Owls are legally protected against disturbance whilst nesting. However, it’s likely that any owl nest is high above you and if you are quietly collecting pellets on the ground you are probably not going to disturb the owls.

Fresh owl pellets should be thoroughly dried and kept in an airtight container or frozen in an unsealed bag or cardboard box (so they can dry whilst frozen). If moist pellets are stored together they can become a congealed mass of pellet debris. If pellets are stored in a sealed container a number of grubs or small moths may be found once the container is reopened. These are clothes moths and their grubs are completely harmless (except to wool). Freezing kills them. 

In dry, well-used roost sites, lots of Barn Owl pellets can accumulate. Using our owl pellet age guide photo on the right, it’s possible to work out how long Barn Owls have been using the site and how recently the owl was present.

Barn Owl pellets break down with age as clothes moths eat the fur, leaving the tiny bones behind, which can last for many years.

Pellets can be analysed wet or dry. It is easier to analyse dry pellets, but to extract all of the small mammal bones intact, dried pellets can be soaked in water for 24 hours.

Gently tease the pellet apart using your fingers or tweezers. Although pellets do not smell, (they are not faeces) hands should be washed thoroughly with soap and water after this activity.

Many thousands of Barn Owl pellets have been analysed so we know a great deal about what   Barn Owl’s hunt and eat .

Wild Barn Owls eat mainly small mammals such as voles, shrews and mice. Other less common items include rats, birds and frogs.

The simplest way to identify which small mammals have been eaten is to search for the lower jaw bones, then ‘pair up’ the right and left jaws from each pellet.

The shapes of the bones, particularly the jawbones, can tell you what species of animal the owl has eaten. You can also count how many prey items are contained within an individual pellet.

Take a look at a our photos of owl pellet analysis to help you to identify bones

– free* PDF to download. Includes owl pellet analysis diagrams. *Free for personal and educational use only – copyright Barn Owl Trust.

Barn Owl Trust Owl pellet dissection pack

Contains everything you need for owl pellet dissection – including a real Barn Owl pellet! Natural science straight from the owl’s mouth! Owl pellet analysis is a fascinating activity for adults and children. You can buy the packs from our  online shop .

Other relevant pages

Photos of owl pellet analysis – bone identification

Owl pellet facts for kids

Barn Owl hunting and feeding – what do Barn Owls eat and how do they hunt?

Signs of Barn Owl occupation – are Barn Owls living in your barn?

Owl Pellet Dissection

Activity length, animals ecology and evolution, activity type, exploration.

In this activity, students dissect owl pellets and reconstruct the skeletons of animals inside to discover what the owls have been eating. 

When you first see an owl pellet, you will probably think that it is feces, but this pellet has been regurgitated from the other end, the owl's beak.

Owls are predators and usually swallow eat their prey whole, or a least in large chunks complete with bones, fur, and feathers. Prey species can include rodents, insects, lizards, rabbits, bats, snakes & birds, to name a few. In the owl's stomach, the soft matter is digested, but the fur and bones are regurgitated back out through the mouth in a little package, or pellet.

Pellets are important for scientific study because they give us a picture of what the owl eats, when, and in what frequency. The last time you read in some book what an animal eats, did you wonder how some scientist was able to learn that information? It would be too difficult to follow the animal around and watch it eat, especially at night when most owls feed. This means we have to examine things like pellets.

Vocabulary:

Regurgitate: to bring (swallowed food) up again to the mouth.

Ornithology: the scientific study of birds.

Pellet: In ornithology, is the mass of undigested parts of a bird’s food that some bird species occasionally regurgitate. The contents of a bird’s pellet depends on its diet, but can include the exoskeletons of insects, indigestible plant matter, bones, fur, feathers, bills, claws, and teeth.

Dissect an owl pellet and reconstruct the bones of the owl’s regurgitated waste.

Explain how scientist can determine what an animal eats by examining its waste.

Per Group: 1 pair of gloves dissection tray containing: Owl pellet*, Probe, Tweezers index card or paper plate on which to glue the various bones extracted from the pellet paste skeletal diagrams of some typical owl prey. Some are available at Barn Owl Trust or Owl Brand Discovery Kits . magnifier (optional)

*Owl pellets are available through online educational supply stores such as Boreal , or at your nearest owl sanctuary. They have been dried and gassed to kill all bacteria and parasites and are perfectly safe to touch.

Key Questions

• What types of animals do owls eat?
• What animals do you think this particular owl has been eating?
• Why are the fur and bones not digested?
• What owls do we have in our region?
• What owls are on the endangered species list?
• Discuss what an owl pellet is and predict what might be found inside before distributing the pellets, dissection tools and gloves.
• Dissect the pellets carefully.
• Observe that the pellets are composed of both fur and bones of the prey.
• Pull the bones out ofthe compacted fur.
• Sort the bones by type (skulls,ribs, vertebrae, leg bones).
• Decide how many prey animals are present. Note that there may only be one.
• Try to sort the bones to go with each skull found, using the skeletal diagrams as a guide.
• Glue the bones to the card, one card for each animal, labeling the bones if possible.
• Compare the types of prey found in each groups’ owl pellet and discusswhatwe can learn about the owl’s diet, behaviour and environment.
• Take students to an owl sanctuary (or OWL rehabilitation center) and observe these wonderful creatures in the wild (or semi wild) environment.
• Discuss prey species further: What prey species are local? What can their frequency in the owl pellets tell you about the prey? Why is difficult to tell species apart from bones, when they normally look very different?

Other Resources

Barn Owl Trust | Barn Owl Science PDF   & Barn Owl pellet analysis

Audubon | What is an Owl Pellet?

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