A+new+and+improved+system+for+identifying+prey+in+regurgitated+owl+pellets+(a.k.a.,+owl+yak).

Session: A new and improved system for identifying prey in regurgitated owl pellets (a.k.a., owl yak).

April 22, 2009

Attendees: Maxine Barnett Lorne Swarthout Aidan Lucey Maureen Sheehan Ben Chant David Seebaugh (facilitator)

As part of their studies of food chains and food webs, Fourth Grade science students dissect a regurgitated owl pellet, identify prey items found in the pellet and use their data to determine prey distributions and construct hypothetical food chains. The primary objective of this unit is to consider the question, “How is energy transferred and recycled within a community.”

David gave a brief overview of owl digestive anatomy, the dissection process and the method for identifying prey animals used in previous years (using skull keys). (Please click on the link to the powerpoint presentation at the top of this page for pictures/information).

He then described the new method for identifying prey uses incisor dimensions.

Other new additions to the owl pellet project (dissecting pellets from the Northwestern and Southeastern U.S.; estimating prey size using femur lengths) were also discussed.

Session participants dissected a pellet and identified prey items using the new method. Femur lengths were used to estimate prey size.

Advantages and limitations of the new method for prey identification were considered.

Reference: Hager SB, Cosentino BJ, 2006. An identification key to rodent prey in owl pellets from the Northwestern and Southeastern United States: employing incisor size to distinguish among genera. The American Biology Teacher.

-D. Seebaugh