Powers lab news

WE GOT THE COVER! The first publication from my collaboration with Dr. Bret Tobalske at the University of Portland made the cover of the March issue (207(8)) of the Journal of Experimental Biology.

Cover: One of the smallest flying vertebrates, a rufous hummingbird, takes to flight from a perch instrumented with strain gauges to measure forces exerted by the bird's diminutive hindlimbs (photo by Douglas Altshuler). The inset graph shows vertical and horizontal reaction forces during take-off. B. W. Tobalske, D. L. Altshuler and D. R. Powers demonstrate the consequences of morphology and motivational state upon take-off performance in hummingbirds (p. 1345-1352).

Biologists are often creative when the schedule professional meetings. When I was invited to participate in a symposium on "Hybernation and Torpor in Birds" at the upcoming Life in the Cold conference I agreed quickly once I found out that the meeting would be held aboard a cruise ship traveling from Vancouver, BC to Seward, AK. My symposium talk will cover work done in my lab on how social interaction among hummingbirds impact their use of torpor. I have already completed a manuscript on the subject that will be published in a book along with other symposium papers. The conference runs July 25 to August 1 2004.

PUBLISHED IN NATURE! Along with my collaborators Dr. Doug Warrick (Oregon State University) and Dr. Bret Tobalske (University of Portland) we published our finding that hummingbirds do not produce equal lift during up and downstroke while hovering. Data from our study will drive a re-examination of the evolution of hummingbird flight. the study can be found in the June 23rd 2005 issue of Nature (435:1095-1097).

Image: The proximal part of the wing, to the left of the yellow line, is not as supinated (inverted) as the distal portion, to the left of the red line. The presentation of these two protions of the wing is typical for an avian upstroke, and results in an airfoil of reduced efficacy relative to the downstroke.