Owl Pellet Dissection: Identify Bones and Ecological Insights

EXERCISE 1: OWL PELLET DISSECTION Pictures of the bones (4 points)- You will need pictures of your owl pellet before dissection and after. These are required in order to receive credit for this lab. Your after photo should include ALL your bones arranged by bone type (e.g. all the skulls in one pile) and neatly organized (this will show effort). You will need to identify the bone types (i.e. identify ALL the different types of prey found). In each photo, please also include your ID or something with your name and class section written on it. Table 2. Owl Pellet Characteristics – 1 point Pellet Length (cm) 4cm Pellet Width (cm) 3cm Other Characteristics (Describe) The owl pellet is black. It looks like a rock with white spots throughout the black pellet. It looks chalky. Cylindrically shaped and smooth. It looks like there are furry things in it. Table 3. Owl Pellet Components – 3 points Be sure to use the key to identify the bones in your owl pellet. Vertebrae are very small so you need to be meticulous and careful when pulling the fur from the bones. Carefully count and show these in your pictures (e.g. if you say you have 20 ribs then the photos should show 20 ribs) Type of Bone Animal Source Number of Bones Skull Rodent, bird, mole 3 Jaw Rodent, bird, mole. Shrew 4 Scapula Rodent, bird, mole, shrew 4 Rib Rodent, bird, mole. shrew 11 Vertebrae Shrew, mole, bird 4 ©eScience Labs, 2018 Ecology of Organisms

Type of Bone Animal Source Number of Bones Hindlimb Rodent. Shrew, mole 5 Forelimb Rodent, mole, bird, shrew 4 Pelvic Bone Rodent, mole, bird, shrew, bird 4 Exercise 1 Post-Lab Questions 1. What were you able to identify in your owl pellet (be specific)?. 1 point I was able to identify the skull, ribs, pelvic bone, and jaws. The ribs were small and round for the most part very easy to identify. The skull was also easy to identify you could tell which skull belonged to what animal. The jaw was also very easy to identify they were like one another some were larger than others. The pelvic bones were very similar to the little hoop on the ends and were the easiest to identify. 2. What can you infer about the community (what type of environment) in which the owl lives? Why did you infer this? 2 points The owl must live in urban ecosystems such as cities and they hunt small animals that possibly live in fields. I infer this because the bones found in the pellet are all the same. There was not an out of the normal type of bone found in this. 3. List the possible ecological interactions between the organisms listed below. Hint: Use Table 1 in the introduction. 4 points a. Owl-Owl: competition; they are both the predators and depend on the prey for food and competition is the negative interaction when the species depend on the same food chain. b. Owl-mouse: predation; the owl is the predator, and the mouse is the prey. Predation is the interaction in which one species which is the predator benefits while the other species which is the prey is harmed. c. Owl-trees: commensalism; the owl benefits from having a place to build their home and trees are not harmed by their presence. Commensalism is the interaction where one species is benefited while the other remains unharmed. ©eScience Labs, 2018 Ecology of Organisms

d. Owl-tick: parasitism; the ticks attach to the owls and feed off them. Ticks are benefited while the owls are harmed in this situation. Parasitism is the interaction where one organism which is the parasite lives on or inside other organisms such as the owl and causes it harm. 4. Other birds of prey produce pellets as well, and the contents of the pellets are dictated by where the bird lives. What would you expect to find in a pellet from a shorebird, such as a seagull? 1 points Seagull bird pellets contain crab, bones, fur, and feathers of birds. We may also find small fish in them since they are close to the sea and hunt small animals from the sea or around the sea. 5. What is the problem with putting out poison for mice or other animals people consider to pests? 1 point We are killing animals that other animals prey on. Therefore, making It harder for them when it comes to finding their prey. We are also putting the environment and other animals at risk especially if they eat them it can poison them and possibly kill them too. 6. Be creative and create a food chain with 4 trophic levels. 2 points (Producers) Plants > (Herbivores) Squirrels > (Primary Predators) Frogs > (Secondary Predators) Fox 7. Why is it challenging to create a good chain with 6 trophic levels? 1point Creating a good chain with 6 trophic levels is challenging because it requires a large amount of energy and resources to sustain each level. As energy is transferred from one level to the next there could be a loss of energy which then results in less energy available for the higher tropic levels and it makes it difficult to maintain a stable flow of energy throughout the entire chain. ©eScience Labs, 2018 Ecology of Organisms

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OwlPelletLabAssignment (1)

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