The owl pellets that you will be examining in this lab have been collected and fumigated from common barn owls. Owl pellets themselves are ecosystems, providing food and shelter for communities which may include clothes moths, carpet beetles and fungi. Clothes moth larvae are frequently abundant in pellets, feeding on fur and feathers. The black spheres about the size of periods (.) that are found in the pellets are the droppings of the caterpillars. The larvae metamorphose near the surface of a pellet in cocoons made of fur.
1. Length of your owl pellet_______ Average length_______ Width of your owl pellet_______ Average width_______ Mass of your owl pellet_______ Average mass_______ 2. Total number of prey animals found_______ Birds_______ Rodents_______ Insects_______ Other_______ Average number of prey per pellet_______
1.If a barn owl produces one pellet each day, estimate how much food the owl would eat in a year. (Show your work.) 2.The average adult barn owl requires 80 to 100 grams of food daily. Find out how much a typical adult barn owl weights, and calculate the percentage of its weight that it must consume daily to survive. weight of prey / weight of owl= % of weight 3.Do you think an herbivore would consume a larger or smaller % of its weight that a carnivore? Why or why not? 4.Environmentalist are concerned about the accumulation of certain poisons in the body systems of predators. Why do you think owls, eagles, swordfish, lions and humans are often the most threatened organisms in a community that is exposed to DDT or mercury? (Both DDT and mercury are stored, not broken down in animals) 5.On the other side of this paper, construct a diagram of a food web (of at least 15 animals) with an owl at the uppermost trophic level. Use an arrow to show which organism in the consumer or predator. 6.Use the following diagram to reconstruct the skeleton of one of the prey items consumed by your owl.