Lisa Lanza
Manlius Pebble Hill
Biology (9th grade)
Host Teacher: Susan Loedel
Lesson Title:
Owl Pellet Lab
Lesson Objectives:
Study the food consumed by owls
Classify the different prey species found in the owl pellet
Through the dissection and interpretation of an owl pellet, students will demonstrate an
understanding of predatory/prey relationships in a food web.
Teaching Standards:
Standard four: The Living Environment; Key idea 1. Living things are both similar to and
different from each other and nonliving things.
Performance indicator: Students explore the characteristics of and differences between living and
nonliving things
Sample task: Conduct investigations, collect data, and record observations: Record data of the
number and type of vertebrate or invertebrate material found in the owl pellet. Use the
dichotomous key and diagrams provided to identify your sample from the skulls found. Record
the name of each species found.
Key Idea 6. Plants and animals depend on each other and their physical environment.
Performance indicator: Describe the flow of energy and matter through food chains and food
webs. Sample Task: Students will during analysis and conclusion of this lab and during class
discussion describe the trophic level and food chain of barn owls and their prey species.
Content / Concept overview:
Energy flow within ecosystems
Predator/ prey relationships
Dichotomous key of owl prey
Key Terms:
Habitat
Dichotomous key
Predator
Prey
Energy flow
Trophic level
Niche
Birds of prey
Lesson placement:
The owl pellet lab will merge existing class discussion and study of ecosystems, habitats, energy
flow within ecosystems. The owl pellet lesson will blend concepts from previous chapters with
new concepts from chapter 18. The students have not yet read chapter 18 and this will be an
opening activity to the concepts yet to be discovered. See discussion of chapter 18 at the end of
lesson plan.
Instructional order:
Teacher (20 minutes)
Discussion of barn owl key characteristics
and their various adaptations that allow
them to be successful nocturnal predators.
What trophic level do owls belong to?
What might a food chain in an owl’s
habitat look like?
How might they differ from songbirds?
Different beaks (for tearing flesh),
songbird/cracking seeds, hummingbird
/nectar. Different feet design one for
perching and talons for grabbing prey.
Talk about differences and similarities of
birds of prey specimens.
Owl fact sheet: (hand out)
Students
Students will contribute to the discussion
and observations of barn owl specimens
and feathers. Students will use field guides
to learn about their habitats, sizes, and
behaviors of the owl and its prey.
Taxidermist specimens on loan from E.S.F
will allow students to have first hand
observations of barns owls and hawks
(birds of prey) and one prey species. Owl
feathers will be available for the students to
compare and contrast and listen to
differences in silent flight of owls versus
those of another bird species. Students will
be able to make observations about the two
birds of prey species.
How are owls related to other birds?
We will discuss and read the section that
describes nocturnal and diurnal birds of
prey. Specimens of both birds of prey will
be available to make observations on how
they differ and are similar.
Lab objectives: (5 minutes)
To study the food items (prey) consumed
by owls. A dichotomous key and field
guides will be used to classify the prey and
to determine characteristics.
What is an owl pellet? How is it created?
Prelab:
What are some ways you can predict which
species of animals you might find in an owl
pellet?
In what way might the formation of owl
pellets increase an owl’s survival in an
ecosystem?
Read and discuss key concepts of the lab
Dichotomous key
Owl pellet
Discussion of pellet formation and owl
digestive processes.
Make predictions about types of prey
by studying the ecosystem of the owls and
by using resources to research owl life
history
Swallowing prey whole requires less time
on the ground, thus the owl is less
vulnerable to predation itself.
Materials: (50 minutes)
Procedure and data collection:
Identification guides to birds and mammals
Owl pellets
Paper towels
Needle probe
Fine forceps
Hand lens
Dichotomous key
Field guides and diagram sheets
In lab groups:
A. Dissection
1. Working on a piece of paper toweling
carefully tease apart the pellet with you
needle probe and forceps. Gently remove
all the bones, teeth, and any other animal
material from the fur.
2. Spread out another piece of paper
toweling and group all similar bones or
invertebrate materials together in small
piles.
B. Identification
1. Record on the data sheet the number of
each type of vertebrate or invertebrate
material found in your pellet.
2. Using the dichotomous keys and
diagrams provided identify the animals in
your sample from the skulls found.
3. Record the name of each species
identified in the student column of the class
data table.
Wrap-up 5 minutes
Based on your findings are an owls prey
more of an r-strategist or a K-strategist?
Why? Trophic level, size and habitat
C. Class data
1. Record the number of each species found
by the class in the class column of the data
table.
2. Calculate the percentages of each prey
species found by the class.
3. Using the field guides identify the
habitats, sizes and behaviors of the barn
owl and of the common prey species found
by the class.
Students will clean up their lab stations and
discuss the final concepts before being
released from class.
Describe an owl’s Niche in terms of
trophic level. Size, habitat and behavior.
Habitat: open country, forest edges,
cultivated areas, cities.
Behavior: Time of activity: nocturnal, very
quiet.
Diet: eats mostly rodents, uses acute
hearing to locate prey.
Students will have this information as part
of the lab to complete the niche chart as
part of the lab activity.
Discussion of a Barn Owls niche.
Define Niche:
The functional role of a particular species
in an Ecosystem. How an organism lives,
the “job” it performs within the ecosystem.
Extending activity:
Students will complete the analysis and conclusion section of the lab for homework.
1. What types of vertebrate material were found in your owl pellet? Remember the bones
and teeth are not the same type of material.
2. List the name and number of all the separate species of animals found in your pellet.
3. What animals are represented most often in the diets of the owls your class studied?
4. List the most common species found.
5. Would you consider most prey species more of an r-strategist of K-strategist? Explain.
6. What generalizations can you make about the relative size of the populations of the most
common prey species compared to the Barn Owl population?
7. How do owls help to maintain the carrying capacity of their prey populations?
Next class:
We will pick up from the niche discussion and extend it to discuss how some niches may
overlap. For example the niche of a barn owl that eats rodents is that of a secondary or tertiary
consumer a predator but not a top carnivore. The niches of some organisms overlap. If the
resources that these organisms share are in short supply, it is likely that there will be competition
between organisms. The discussion will lead the way to Chapter 18 and how competition shapes
communities and how organisms interact in communities (the major concepts of the chapter).