I am interested in the ecology and behavior of small mammals, particularly cryptic species that present challenges to capture and monitor such as shrews and small mice. I have adapted radio transmitters for use with these tiny species (space use and movements of short-tailed shrews) and designed special traps to maximize capture success (ecology of the eastern harvest mouse). I also have a strong interest in science education, and I am especially interested in methods of teaching and learning that improve science literacy for the general population.
Areas of Expertise (4)
Bowling Green State University: Ph.D.
Old Dominion University: M.S.
JM Cawthorn, DL Morris, ED KETTERSON, et al.
Testosterone affects the allocation of reproductive effort in male birds. Elevated testosterone causes male dark-eyed juncos,Junco hyemalis, to decrease care of dependant offspring, but this generalization is based largely on reduced provisioning rates by males treated with testosterone. Therefore, we used a predator model to explore the relationship between testosterone and nest defence, a more immediate measure of male parental effort. Control males (C-males) were more likely to respond within 10 min to a mount of an eastern chipmunk,Tamias striatus, placed at the nest than were testosterone-treated males (T-males)...
LA Klukowski, JM Cawthorn, ED Ketterson, et al.
An earlier study of free-living male dark-eyed juncos found an increase in plasma corticosterone (B) in response to experimental elevation of plasma testosterone (T) (E. D. Kettersonet al.,1991,Horm. Behav.25,489–503). To investigate whether the increase was caused by enhanced secretion of corticosterone or by a slower clearance rate, or both, we exposed 52 captive yearling male dark-eyed juncos (Junco hyemalis) to day lengths corresponding to those of spring and implanted them with one or two testosterone-filled or sham implants (10 T-I, 22 T-II, and 20 C-males). We then examined the effect of experimentally elevated testosterone on plasma corticosterone and on corticosteroid-binding globulin (CBG), as measured by the ability of steroid-stripped plasma to bind labeled corticosterone...