NOTIONAL OBJECTIVES :

Analysing owl regurgitation pellets teaches us what these animals eat and therefore their diet.

METHOD OBJECTIVES :

 to dissect an owl regurgitation pellet
 to present one’s result in an organised manner
 to use a identification key from the bones of a regurgitation pellet
 to make a bar chart

MATERIALS :

 owl regurgitation pellets
 bowl, thin pliers
 sheets of drawing paper
 identification key from the bones found in regurgitation pellets (cf. schoolbook)
 photo of a classified content from a regurgitation pellet (cf. schoolbook)

Procedures :

Use the following worksheet :

1. Dissect an owl regurgitation pellet

 Describe the regurgitation pellet : shape, colour, size…
 List the elements composing the pellet. Take off the bones and clean them. Classify them (skull, limb, pelvis, ribs, teeth…)

2. Analyse the regurgitation pellet content

From the photographed pellet content, indicate, justifying the answer, the number of preys eaten by the owl. With the identification key given, establish the name of the eaten animals.

3. Read and make tables

The following table shows the tawny owl’s diet :

Represent the table as in a bar chart.

ASSESSMENT :

Capacity for the pupil :

 to analyse a regurgitation pellet content
 to deduct the owl diet
 to understand and re-use the used methods (dissection, display of results in tables, use of identification keys)

Jean-Michel Josse professeur de Sciences de la Vie et de la Terre, Lycée Français Charlemagne de Pointe Noire, Congo Brazzaville