Shealer, David A.

Courses taught at Loras:

Bio 116: Principles of Biology II
Bio 279: Experimental Design/Biostatistics
Bio 231: Vertebrate Zoology
Bio 310: Animal Behavior
Bio 330: Evolutionary Ecology
Bio 375/Hon 273: Conservation Biology

Why advise student to come to Loras? I joined the Loras Biology Department in 1998.I came to Loras because I was impressed with the quality of the faculty and students.All members of our department are deeply committed to providing our students with a first-rate education.Our small size enables us to get to know our students quickly, cultivate their strengths, improve their weaknesses and prepare them for a career in the biological sciences.We emphasize undergraduate research here and provide numerous opportunities for students to engage themselves in an active research program.Research experience gives our students a competitive edge when applying to graduate or professional schools.

Rewarding aspects of being a faculty member at Loras. At Loras, you’re not just a member of a particular department, you are part of a larger community.All of us share the common goal of educating our students to the best of our abilities.As such, one of the most rewarding aspects of being a professor at Loras is seeing students forge new connections, gain new insights and develop confidence in their own abilities.

Research Interests: My main research emphasis is on the ecology and behavior of aquatic birds, particularly terns (Sternini).  Since joining the Loras faculty in 1998 I have been studying the population demographics of black terns in central Wisconsin. Black terns are a bioindicator species of the health of freshwater ecosystems and are a species of conservation concern due to a drastic decline in numbers over the past century. My students and I are investigating the breeding and feeding ecology of black terns during the summer. This work involves trapping and banding birds and determining reproductive success.We also are using molecular markers to determine the sexes of adults and chicks. This information enables us to test evolutionary hypotheses regarding sex-ratio variation in populations and to examine the potential for females to manipulate the sexes of their offspring under various circumstances. Closer to home, my students and I have been investigating the evolutionary ecology and physiology of insects that inhabit goldenrod plants.Several insects overwinter inside galls formed on the plant stem and must withstand extended periods of subzero temperatures. Recently we have been conducting experiments to determine factors responsible for the timing and extent of freeze tolerance in these insects, and the biochemical changes associated with the onset of freeze tolerance. more on the population biology of Black Terns...

Recent Publications(*denotes undergraduate student coauthor)

Shealer, D. A. and C. M. Cleary. 2007. Sex determination of adult Black Terns by DNA and morphometrics: tests of sample size, temporal stability and geographic specificity in the classification accuracy of discriminant function models. Waterbirds, in press.

Shealer, D. A., *J. M. Buzzell, and *J. P. Heiar. 2006. Effect of floating nest platforms on the breeding performance of Black Terns. Journal of  Field Ornithology 77:184-194. (pdf)

Shealer, D. A., J. A. Spendelow, J. S. Hatfield, and I. C. T. Nisbet. 2005. The adaptive significance of stealing in a marine bird and its relationship to parental quality. Behavioral Ecology 16:371-376. (pdf)

Shealer, D. A., J. E. Saliva, and J. Pierce. 2005. Annual survival and movement patterns of Roseate Terns breeding in Puerto Rico and the U.S. Virgin Islands. Waterbirds 28:79-86.

Shealer, D. A. and J. A. Spendelow. 2002. Individual foraging strategies of kleptoparasitic Roseate Terns. Waterbirds 25:436-441. 

Shealer, D. A. 2002. Foraging behavior and food.Chapter 6 in Biology of marine birds (E. A. Schreiber and J. Burger, Eds.). CRC Press, Boca Raton, FL.

Shealer, D. A. and *J. A. Haverland. 2000. Effects of investigator disturbance on the reproductive behavior and success of Black Terns. Waterbirds 23:15-23.

Shealer, D. A. 1999. Sandwich Tern (Sterna sandvicensis).In The Birds of North America, No. 407 (A. Poole and F. Gill, eds.). The Birds of North America, Inc.,Philadelphia, PA.

Shealer, D. A., *J. P. Snyder, *V. C. Dreisbach, *D. F. Sunderlin and J. A. Novak. 1999.Foraging patterns of eastern gray squirrels (Sciurus carolinensis) on goldenrod gall insects, a potentially important winter food resource. American Midland Naturalist 142:102-109.

Shealer, D. A. 1998. Size-selective predation by a specialist forager, the Roseate Tern. Auk 115:519-525.

Shealer, D. A. 1998. Differences in diet and chick provisioning between adult Roseate and Sandwich Terns in Puerto Rico. Condor 100:131-140.

Zurovchak, J. G. and D. A. Shealer. 1996. Mortality sources of Eurosta solidaginis (Diptera:Tephritidae) inhabiting single versus double-galled stems of goldenrod. American Midland Naturalist 136:94-100.