Owl Pellet Lab Name: ______

Science 10

Pre-lab On-line Activity: Use the Internet to search for answers to the following questions:

  1. What is an owl pellet and how are they formed?
  2. Owls are a type of raptor. Define this term and name two other types of raptors.
  3. What is the typical habitat of a barn owl?
  4. List three types of prey that owls eat.
  5. How might an owl pellet be a miniature ecosystem?
  6. Seagulls also form pellets. What might you expect to find in their pellets?
  7. How do eagles and hawks differ from owls in the manner that they eat their prey?
  8. What does the term regurgitate mean?
  9. Describe four adaptations that owls have that make them great hunters.
  10. What human activities might interfere with an owl’s niche? In other words, how are humans encroaching on owls’ territories?

Lab Day Activity: In your group, follow the instructions and answer the questions as you work on the dissection.

  1. Before opening the pellet, make a prediction as to what you think the pellet will look like when it is unwrapped.
  2. Carefully open the aluminum foil wrapper that surrounds the pellet.

3. Measure and record the length, width and mass of the pellet.

4. Record other features (colour, smell, texture...) of the pellet before you start to dissect it.

5. Using the dissecting probes and tweezers, carefully pick apart the owl pellet, being sure to not break any bones that are in the pellet. Do this on a white piece of paper so as to not lose any pieces of the pellet.

6. Using the bone identification sheets provided to your group, attempt to categorize the bones. First, organize them according to type of bone. Then try to determine what type of predator the bone came from. For example, if you’ve found a few skull bones put them together. Then, try to figure out which type of skull it is.

7. Create a data table like the one below to tally the numbers of each bone found:

Bone / skull / jaw / scapula / forelimb / hindlimb / pelvic bones / rib / vertebrae
Type of prey
number

8. Create a bar graph to represent this data (bone type on x axis; number of each bone on y axis)

9. Create a full skeleton as best as you can by organizing your bones into the shape of the prey that you think you have. Using either glue or tape or a combination of the two, mount the bones on paper. Place any extra bones that you feel don’t fit into your skeleton on the side of your paper, but be sure to label them according to bone type.

10. How many prey do you think the owl ate and regurgitated in this pellet?

11. Construct a food web, using the owl and the prey found in the pellet and any other organism that you feel would be appropriate.

12. In which trophic level would you categorize the barn owl?

13. Does the fur present in the pellet help you to identify the prey? What uses does the fur have for small insects?

14. Define the term biomass. How would the mass of the pellet be different if it were fresh from the mouth of the owl?

15. Aside from bones and fur, what other material did you find in the owl pellet? What does this indicate with regards to the importance of owls in an ecosystem?

Marking:

Your group will receive a group mark for the mounting of the bones. This should be neatly organized.

You will receive marks for the following:

·  lab behaviour / participation /group work / clean-up

·  the questions (from procedure) neatly answered

·  the graph / data table completed

·  the pre-lab questions completed