Research Program & Student Research

    How scanty an account even the wisest among us can give of this earth on which all our days are spent.                                                                                          -Edwin Way Teale, A Walk Through the Year

Godard Homepage

My research interests focus primarily on understanding how organisms interact with their environment.  Many students have worked with me on the research projects that I describe below.  I have also supervised other student initiated research projects in behavior, ecology and environmental science.

 

Much of my dissertation research focused on acoustic communication in birds.  Unfortunately, birds sing primarily during the breeding season which does not coincide with the academic year for students.  As such, I have not done as much research in this area with students.  However, during the spring and summer of Becky Hylton's ('97 honors biology student) junior year, we recorded the songs and mapped the territories of over 40 indigo buntings in the fields and forests near my home.  Like other migratory birds, male indigo buntings return in the spring to North America and establish breeding territories.    They defend these territories and advertise for females using songs.  Previous research had shown that the properties of songs produced by some species of birds are suited for long-distance communication in the particular habitat in which they breed.  Specifically, birds that sing in the forest avoid avoid using high frequency notes and notes that are repeated rapidly, because forests have a multitude of reverberating structures.  Interestingly, about half the indigo buntings we recorded had territories in open habitat and the others had territories in forested habitat.  After computer analysis of the song properties, we did not find any differences in the songs  produced by male indigo buntings (Hylton & Godard, 2001).  We found that buntings that nested in forested habitat tended to sing from the tallest trees on their territories.  Perhaps singing from such height, reduces the amount of reverberation the songs receive as they travel through the environment.

Do song properties of indigo buntings breeding in fields differ from those breeding in forests?

 

Indigo bunting

 

 

 

How do fish detect aquatic predators?

 

 

 

    Golden Shiner

 

After watching fish in a small stream near my home, I became interested in how fish detect predators, particularly snake predators. For the last four years, Bonnie Bowers in the psychology department and I along with many student researchers have been examining that question in our laboratory at Hollins.  Though I prefer to carry out research projects in the field, the laboratory environment can sometimes offer a more controlled setting in which questions can be more clearly answered and laboratory research certainly works better with student schedules.

Most small prey fish in freshwater streams are members of the superorder Ostariophysii, a group of fish that contain alarm chemicals in their skin.  Previous research at other universities had shown that predatory fish that have eaten ostariophysans become “marked” by this alarm substance.  Naïve prey fish that are exposed to chemical byproducts (urinary, respiratory, skin chemical and feces) from these marked predators will flee and exhibit other antipredatory behavior.  We were initially interested to see if snake predators could also be “marked” by eating ostariophysans.

 

Can naive golden shiners detect northern water snakes by chemical cues alone? Catherine Wannamaker (’96, honors biology student), Bonnie Bowers and I carried out several experiments and found that golden shiner minnows (an ostariophysan) would exhibit antipredator behavior when exposed to waste byproducts of marked Northern water snakes.  However, when the shiners were exposed to skin chemicals from “marked” snakes, they did not show antipredator behavior (Godard et al., 1998).  Northern water snakes are often sit-and-wait aquatic predators and forage at night, thus they provide very few visual or motion cues to the fish that they prey upon.  Moreover, like all snakes, they produce waste byproducts infrequently.  Thus these shiners would be vulnerable to attacks from snakes unless they could learn to respond to chemicals released from snake skin.

Northern Water Snake

Northern Water Snake foraging for shiners during conditioning trials.

 Can naive golden shiners learn to detect chemical cues from snake predators?      Julie Zalenka (’99, honors biology student), Martha Tubman (’00, honors biology student), Bonnie Bowers and I devised a series of experiments that examined the ability of naïve golden shiners to learn to detect skin chemical cues from "unmarked" snakes.  Previous research with other fish species had shown that these fish could learn to respond (or condition) to neutral chemicals after concurrent exposure to these neutral chemicals and the alarm substance.  Our research showed that shiners showed a weak ability to learn to respond to chemicals from one aquatic snake predator, northern water snakes, but showed no conditioning to plains garter snakes, another predator.  Moreover, only the most realistic conditioning experiences we devised resulted in any demonstrable learning by shiners (Godard et al., submitted).

Future Thoughts

 The results from these experiments have led to more questions:  Can shiners learn to recognize snake predators if laboratory conditions more closely mimic their natural environment?  How do the chemicals released by snakes differ among the various species? 

Other research has documented that shiners coexist more readily with fish predators than do other ostariophysans.  We would like to compare the responses to chemical cues from predators of shiners with other minnows (e.g. fathead minnows) under similar laboratory conditions.   We look forward to examining these questions with future student collaborators.

                  One pair of bird boxes

             Black rat snakes in boxes

           Ripped bird box, cast of left hind foot of a very large black bear

Can hole nesting birds detect snake predators by chemical cues?  

The most recent project I’ve begun ties my love for birds into my developing interest in detection of chemical cues.  While examining the literature on chemical detection of predators, Bonnie Bowers and I became aware of the paucity of data on chemodetection of predators by birds.  In fact we could only find a couple papers that described research that examined this issue.  It’s possible that few people have looked at the question because of the assumption that birds, like humans, rely more heavily on other sensory information (e.g. sight).  But the dark confines of a natural cavity (or birdbox) do not provide visual cues of predators that may frequent that space. 

So during my sabbatical (‘00-’01) I initiated an experiment to examine if hole nesting birds can detect chemical cues from snake predators.  In the initial study, I  placed 18 pairs of bird boxes in the woods surrounding my house.  Weekly, I scented half of the boxes with paper laced with waste byproducts from black rat snakes and the other half with paper laced with water.  I was hoping to examine the pattern of box choice among woodland hole nesters (e.g. tufted titmice and chickadees).

Bears found the boxes of great interest as did wasps and woodroaches. Unfortunately, the titmice and chickadees that have territories in my study area chose natural cavities instead of my boxes. So I hope to continue this work on campus next year, with boxes that I will set up in the fields for bluebirds.  It is my hope that bluebirds will have few natural cavities to choose from and thus may choose among the nestboxes that I provide. 

 

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