Owl Pellet Dissection- Hoot and Hurl!
Background Information: Use the resources provided or the Internet to answer the following questions
on your own paper.
1. What are owl pellets?
2. What happens to the soft parts of the prey?
3. What is the purpose of the gizzard in the owl pellet formation?
5. Where does the pellet remain until it is expelled? How are pellets regurgitated?
6. How often does an owl regurgitated a pellet?
7. List at least 3 other birds that are known to regurgitate pellets.
8. How many pellets does the common barn owl produce per day?
9. What color are the pellets when fresh?
10. Why are the pellets fumigated?
11. Owl pellets not only can give us information about the diet of the owl, owl pellets also provide a habitat for
other animals. In fact, an owl pellet is a little ecosystem all on its own. What kind of animals are found in the
owl pellet ecosystem?
Purpose: You will dissect an owl pellet to determine what an owl eats. You will identify the various organisms found
within the pellet and organism the skeletal/structural remains of the organisms.
Materials: owl pellet, dissecting needle/toothpicks, forceps, black construction paper, bone identification charts, plastic
tray, small cups/containers, gloves
Procedure:
1. Measure the length, width and mass of your owl pellets.
Length of your owl pellet_______ Width of your owl pellet_______ Mass of your owl pellet______
2. Hypothesize: Do you think that the size of the owl pellet is related to the number or amount of prey that is in
the pellet?
3. Carefully examine the exterior of the pellet. Describe the exterior in detail (fur, feathers, color, texture, etc.)
4. Carefully use a toothpick or dissecting needle to break apart the owl pellet and observe what is within. Expose
all bones for identification. Use the bone diagrams, charts and dichotomous key to help you identify your bones
and complete the chart below.
Bones Found
Bone
Type of Animal
Total # Found
Skull
Jaw
Scapula
Forelimb
Hindlimb
Pelvic bone
Rib
Vertebrae
5. Organize the bones into groups and label them. Construction paper will serve as a mounting surface. Your grade
for this portion will be based on neatness, labeling accuracy and organization.
6. Use the different skulls you found to determine the total number of different species in your pellet. Record the
total number of organisms found in your pellet. Then, record the length, width, mass and number of organisms
from five other groups.
Group/Names
(Your Group)
Length
Width
Mass
# of
Organisms
Types of Species
Analysis/Conclusion (Please answer all questions on your own paper):
1. What similarities and differences exist between the pellets of different groups (refer to the group data)?
2. Does the size of a pellet have any correlation with the number of organisms found within the pellet? Use the
data collected to support your response.
3. What do we know about the digestive system of an owl based upon the pellets?
4. Other types of birds form pellets. What would you expect to find in the pellet of a seagull?
5. Owls, hawks, and eagles are types of raptors, animals which have hooked beaks and sharp claws, and are
therefore adapted for seizing prey animals. Hawks and eagles differ from owls in that they eat their prey animals
by tearing them into small pieces, picking out the flesh and avoiding most of the fur and bones. They also have
strong stomachs which can digest most of the bone material which they might eat. The relatively small amount
of indigestible bone and fur that remain will be compacted by their stomach muscles into a pellet similar to the
owl's.
Do you think an eagle pellet would be as useful for dissecting as an owl's? Why or why not?
6. Construct a diagram of a food web (of at least 10 animals) with an owl at the uppermost trophic level. Label all
of the organisms (producer, type of consumer, etc.).
7.
How do food webs and food chains differ?