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Slide 2 Owl Pellet Investigation By: Paige Gottlieb Period 7 Code: 12 Slide 3 Introduction The purpose of this investigation was to find out what the Barn owls eat. To find out what the owls ate, the class had to dissect an owl pellet. Inside of the pellet we found feathers, bones, and fur. When owls eat their prey, they swallow the animal whole, then the owl forms a pellet of the bones, fur, and what ever else the owl can not swallow. Then the owl regurgitates the pellet. Barn owls like every owl are raptors. This means the owls have special adaptations. The owls have sharp talons to rip the flesh of their prey. Owls are nocturnal, they have a keen sense of sight in the dark to spot their prey. They can turn their head 270 degrees the way around, since the owls eye sockets do not move. The owls also have a vivid sense of hearing, which also helps for the owls to find their prey. The Barn Owl is a raptor and hunts very effectively, because of the owls adaptations. This year we had 260 voles, the voles were the most popular animal. Do Brooksides previous years compare to this? Slide 4 Procedure 1.First we measured, weighed, and observed our owl pellets. 2.Then we began dissecting the owl pellets 3.While still in the process of dissecting the pellet, we counted and compared our bones to a dichotomous chart. 4.After finishing dissecting the owl pellet, we began to glue the bones on a diagram of the animal that we had Slide 5 This is a Vole Slide 6 Come on I am a cute little vole. Please don't eat me. Slide 7 Data Tables AnimalVolePocket Gopher MouseShrewRatBirdMoleTotal # found5347000064 Percent83%6%11%0% 100% Prey animals per pellet 1234567>8Total # of pellets in class Total #prey animals in class Number of pellets 248720002364 Percent 9%17%35%30%7%0% 100% Slide 8 AnimalVolePocket Gopher MouseShrewRatBirdMoleTotal # found26027375030332 Percent78%8%11%2%0%1%0%100% Prey Animals per pellet 1234567>8 Total # prey animals in grade Total # of pellets # of pellets 830322011401106331 Percent 7%28%30%18%10%3%0%1%100% Slide 9 Average number of prey animals per pellet Type of prey animal contained by most pellets Number of prey animals contained by most pellets Least to greatest number of prey animals in pellet 3Voles31-8 Slide 10 Comparative Question My prediction is that previous years data will have voles as their most common prey animal. This year we had 260 voles, the voles were the most popular animal. Do Brooksides previous years compare to this? Slide 11 Bar Graphs Slide 12 Comparative question data Years2009- 2010 2011- 2012 2012- 2013 2013- 2014 Voles202306256283 Mouse4672629 Pocket Gopher042129 Shrew7154424 Unknown Rodent 0010 Bird4611 Mole02130 Rat3210 Slide 13 Discussion 1. Scientists use owl pellets to study the owls diet and habitat. The scientists dissect the owl pellets to find all of the bones. Then the scientists identify what prey animal(s) using a dichotomous key. Then the scientist identify where the owls habitat is. 2.In my owl pellet I found 4 voles! I know this because When I was dissecting my owl pellet I had found 4 skulls (3 of them were broken.) I found 14 mandibles and 3 fibulas. 3.The class average for the number of prey animals per pellet was 3 animals. In my pellet I also found 3 animals. About 35% of the grade had 3 animals in their pellet. 4. Based on our data there would be way more prey animals then owls. If their were more owls in the food chain their would not be enough prey for all the owls to eat. The owls only get 10% of the energy so they must eat lots of the prey for more energy. 5.If a barn animal produced two pellets a day, it would probably consume about 42 pellets per week. I say 42 pellets because the majority of the grade found about 3 animals in their pellet. You must multiply three by two because the owl produces two per day. Therefore about 180 animals per month, and about 2,190 per year!! 6.The most common prey species in the grade was the voles. The grade found about 260 voles. 78% of the grade found the voles. From the data I can infer that the most common owls prey in is probably the voles 7.Some farmers around the world shoot the barn owls in fear that the barn owls will eat their chickens. The farmers are wrong for doing that because the owls don't eat chickens. They hunt for animals including; voles, mice, shrew, pocket gophers, birds, and moles. The owl won't eat their chickens. Slide 14 Conclusion The purpose of this investigation was to determine what the Barn owls ate. In Addition I wanted to find out if previous brookside school years had voles as their most common prey animal. My prediction is that previous years data will have voles as their most common prey animal for the owls. My prediction was successful for example in 2011-2012 they had about 306 voles and the voles were their most common rodent. In this investigation there could have been many experimental errors. Some of the experimental errors could be, some students may have counted the amount of animals wrong, or when we put the rodents bones on a presentation sheet people may have put the bones in the wrong spot. Some improvements the whole class could make would be to work more cooperatively, we could all finish the project faster. This lab helped me and my class find out what the Barn owls ate.