Dave Gammon's Research
Research interests
- Cultural evolution and social learning in animals
- Bioacoustics and birdsong
- Animal behavior with an evolutionary focus
- General theory for the progression of all sciences
Potential projects in which undergraduates might get involved (some projects already in process, others still swirling around my head in embryo; talk to me for more details)
- Causes and consequences of vocal mimicry in northern mockingbirds
- Mockingbirds get their name because male mockingbirds frequently
"mock" or mimic the sounds of other species. Although many songbirds
exhibit vocal mimicry, no one has yet done much to examine what
advantages birds gain through vocal mimicry, nor can we do a good job
of explaining why some species are imitated but not others. This
project will involve lots of time outside making audio recordings of
mockingbirds and other species, tracking the reproductive success
of mockingbirds at their nests, and acoustic analysis of lots of
vocalizations.
- Continent-wide geographic variation in the song of house wrens
- House wrens are distributed from the Canadian border down to the
southern tip of South America. While living in Panama a few years
ago, I noticed that the songs of house wrens there sounded more "laid
back" than house wrens in the US. Specifically, the trills of Panamian
house wrens seemed to vary a lot in the number of notes crammed into a
given time period, whereas the trills of US house wrens seemed to
cram in as many notes as possible over a given time period. This
suggests that natural selection on trill rate might vary with latitude.
This project will involve collecting audio recordings from all over
North and South America (mostly through the internet and
correspondence) and then comparing the acoustic structure of songs at a
computer.
- System variability as a predictor of progress in a scientific discipline - While in graduate school in ecology at Colorado State University,
I noticed that ecologists often lament that if only they could
better follow the examples of physicists and chemists, then
ecology would progress more as a discipline. I sometimes hear similar
comments from frustrated social scientists. It strikes me that a
better hypothesis to explain the slow progress of some fields is the
inherent
variability of the systems being studied rather than simply faulting
the people studying the system. We can test this hypothesis empirically
by collecting comparative data from the historical progression of
textbooks and journals in various disciplines of the natural and social
sciences. We can also explore this hypothesis through the use of
computer simulations using a "virtual scientist" who follows
computer algorithms to
uncover patterns in randomly generated data with varying amounts
of complexity.
- How do Carolina chickadees use vocalizations to signal dominance?
- When competing over a food resource as well as during extreme sexual
activity, chickadees use a socially-learned vocalization called the
"gargle". Using an eight-year data set of gargle calls recorded from
black-capped chickadees in Colorado, Mike Baker and I recently
found that dominant black-capped chickadees are more likely to
use gargle calls with special acoustic features. This project
would extend this idea to Carolina chickadees and would involve lots of
time outside setting up bird feeders and then watching birds compete
with each other at these feeders.
- Acoustic constraints on the evolution of birdsong
- Why do sparrows sound like sparrows whereas warblers sound like
warblers? The answer almost certainly has to do with the performance of
the syrinx, which is the voicebox of birds found where the two bronchi
merge into the trachea. We know of anatomical and physiological
differences in the syrinxes of different bird species, and it is likely
that these differences constrain what types of sounds can be
produced by different species. This project will involve lots of time
at a computer analyzing sounds of dozens of species.
- Other possible projects
- How does anthropogenic noise and light affect patterns of animal vocalizations?
- Why do so many birds sing pure tonal songs?
- Are songs with faster trills more threatening to male Carolina wrens?