How can an owl pellet be considered an ecosystem

Warning: Pellets are sterilized prior to shipment, but they have been known to still harbor salmonella and other bacteria. Sterilize area and wash hands after lab. Carefully examine the exterior of the pellet. Do you see any signs of fur? Carefully use a toothpick to break apart the owl pellet and observe what is within.

Use a toothpick to expose all bones for identification. Use the bone diagram to help you identify your bones and complete the chart. Organize the bones into groups and label them, use the attached chart to help you identify bones. Construction paper will serve as a mounting surface. Grade will be based on neatness, labeling and organization.

In so doing, predators help maintain the health and viability of prey populations. All Owls are equipped with special adaptations that make them efficient predators. Keen eyesight allows them locate quarry even on dim nights.

Sensitive, directional hearing helps locate concealed prey. Some species can even hunt in complete darkness using sound alone to guide them to a successful kill. Owl pellets differ from other birds of prey in that they contain a greater proportion of food residue. Birds will barf them back up out of their mouths. These are formed into a pellet, which the owl regurgitates. By dissecting these pellets, one can determine what the owls have eaten. The purpose of this lab is to infer the type and number of prey animals the owls have consumed by examining the contents of their pellets.

Dissecting an owl pellet provides a fascinating insight into the secretive lives of owls. Pellets often contain the remains of 4 or 5 small mammals. Pellet dissection can tell you exactly what an owl has eaten. The bones, fur, feathers and scales remain in the gizzard. After counting the number and variety of prey found within their pellets, students calculate the average diet of a barn owl using the class data.

Note the colour, size and texture of the pellet. Carefully separate the bones from the fur using wooden probes and dissecting forceps.

Identify and categorise the bones, based on type of bone and the animal it came from. Use the Owl Pellet Bone Chart available online to do this. Mice and rats have very similar bone structures.

The main difference is size. A rat will be approximately twice the size of a mouse. Use this information to tell them apart. Record this information in a table like Table 1. Barn owls typically regurgitate two pellets a day, with each pellet generally containing four skulls.

Based on the results of your dissection, determine the type and quantity of animals the owl consumed over 2 days. Gather data from another group to represent the second pellet. Using only whole numbers, record the figures in a data table like Table 2. Using the information in the food web, identify the pattern in food mass consumed for the primary and secondary consumer trophic level.

Consider how the pattern of food mass consumed for the primary and secondary consumer trophic level can be explained using the laws of conservation of matter and conservation of energy.