Owl Pellet Lab I Name ________________________ Purpose:To see what information about an owl’sdiet and niche can be learned from an owl pellet. Background: On the floor of abandoned buildings, beneath a grove of tall trees, or under the structures that offer shelter from inclement weather, you may find signs left by some birds that most people see infrequently. These objects are uniformly dark gray a nd measure from 1 ½ to 3 in ches long and ¾ to 1 inch in diameter. They contain a wealth of information about wildlife. They are owl pellets. Owls are not picky eaters like certain other raptors (animals with hooked beaks and sharp talons [claws] adapted for seizing prey). The owl, like many other birds, swallows its prey whole. Many parts of an animal are not digestible, such as hair, feathers, bones, teeth, and the hard outer shells of insects. The owl’sdigestive system allows it to store these indigestible parts while letting the digestible parts pass to the inte stines. The owl then regurgitates the unwante d parts in the form of a pellet. An owl pellet is a roundish mass that is covered with fur and sometimes feathers from its prey. Fresh specimens are shiny and coated with mucus. Bones and other hard remains are located within the inte rior of the pellet. About 12 hours after consuming a meal, an owl casts, or regurgitates a pellet. Owl pellets are clean of all flesh and virtually odorless. Owl pellets can provide evidence of the owl’sdietary habits and role in its environment, or niche. Owl pellets have been use d for scientific study of small mammals and their distribution. With owls doing the collecting, the scientists must locate the owl roost to obtain the pellets and then study the skulls and bones of small prey living in an area. From these bones the prey species can be counted and identified. The owl plays a role in limiting the population size of its prey. Of the animal species common to an owl’sdiet, the prey species that is most abundant in the area will be the species most likely to be captured and consumed by the owl. This limits the population size of that herbivore, which in turn protects the supply of plants upon which the owl’sprey feed s. Farmers especially appreciate barn owls, which keep populations of crop-eating rodents under control. Materials: barn owl pellet, metric ruler, metric caliper, glass baby food jar with lid, water, dishwashing detergent, cheesecloth, rubber band, blue plastic weighing “boat”,triple beam balance forceps, probe, gloves (optional —provided by student), peroxide solution, 100 ml beaker, white glue, 5 x 8 index card, egg carton. Procedure: Wash your hands thoroughly at the end of each period while doing this lab! 1. Keeping the foil on the pellet, measure and record its length and width in cm using the metric caliper. Record your re sults in Data Table #1. 2. Carefully peel the foil off of the pellet. Place the pelle t in a blue weighing “boat”.3. Examine the outside of the pellet. Use a bulle ted list to describe external features. (space provided on Data Table #1) 4. Place the pellet on the pan of a triple beam balance and find its mass. Record your data in Data Table #1. Remember to subtract the weight of the weighing “boat”!5. Place your “naked”pellet in a clean baby food jar and cover the pellet with water.
