2007 NFSA Cape May Conference Report

[krups1110]

I apologize that it has taken so long, but I have worked with Rick to create a summary of his presentation to remind those who were present at the conference and to allow those not present to see what we all learned about.

Locomotion, Morphology, and Habitat Use in the Southern Flying Squirrel
Richard L. Essner, Ph.D
Department of Biological Sciences
Southern Illinois University Edwardsville

Rick spoke about a number of topics during his presentation, but the three main themes were locomotion, morphology, and habitat use in flying squirrels and their non-gliding relatives. Rick began by providing an introduction to vertebrate gliding and its importance as a repetitive theme in evolution—gliding evolved once in fish, twice in amphibians, nine times in reptiles and birds, and nine times in mammals.

In examining locomotion, Rick quantified and compared 3D Kinematics (movement) in chipmunks (semiarboreal squirrels), red squirrels (tree squirrels), and southern flying squirrels (gliding squirrels). He filmed squirrels during launching, airborne, and landing phases with high-speed video and quantified their movements (e.g., takeoff angles, velocities, limb joint angles). He found that the three squirrels differed in the movement of the tail and forelimbs, but were surprisingly similar in their hindlimb movements.

In flyers, he observed a unique behavior that he termed Asymmetric Limb Rotation (ALR), whereby flying squirrels intitiate alternating rolling and yawing movements of the limbs as they transitioned to gliding. He hypothesized that ALR behavior (not observed in nongliding squirrels) may be a mechanism for dealing with inconsistencies such as angular momentum, fluid dynamics, and turbulence. It also represents an effective means of stretching the gliding membrane (patagium) during deployment. Ultimately, he hopes to conduct modeling experiments to determine the aerodynamic consequences of these limb movements.

Currently Rick is performing nestbox studies in a fragmented suburban forest on the campus of Southern Illinois University Edwardsville. He is capturing, marking, and recapturing flying squirrels in order to measure demographic features of the population and to assess their ability to disperse among forest patches. He hopes to identify what is considered to be suitable habitat in order to assist land use planning. He currently has one student conducting a study to estimate relatedness among flyers who naturally inhabit the same nestbox and another conducting gliding performance studies in an outdoor arena.

Rick’s website is http://www.siue.edu/artsandsciences/biology/ressner/ and he can be contacted at ressner@siue.edu

[Throwaway]

Great work Chris. Is there some place we can monitor his progress?

Colin

[krups1110]

He may update his website with his work. Otherwise, you can keep in contact with the email he has listed. I know Joan definitely will and I will try to stay in contact with him as well so we can update as there is even more progress.

[Joan]

This was filmed while Rick Essner, Ph.D. was doing his master's thesis at Southeast Missouri State. That particular squirrel actually followed him to Ohio as part of his research colony. Rick is in a different segment of the video not shown: http://www.youtube.com/watch?v=_ZgcBUx0 ... re=related