News Spring 2010
Ken Henry succesfully defends his PhD dissertation
Ken has been studying how songbirds process vocal communication signals.
Many of his experiments involved bird species that breed at the Ross
Biological Reserve, including the Carolina chickadee, tufted titmouse,
and white-breasted nuthatch. Ken captured study subjects at the Ross,
and performed a variety of auditory tests in the laboratory before
returning them to their habitat. He used neural responses recorded from
the scalp to assess auditory capabilities. He found that in
general, different songbird species process sound in broadly similar
ways. Species with very high frequency call notes, however, like
chickadees and titmice, are more sensitive to high frequency sounds than
species without high frequency call notes. Furthermore, species with
tonal song notes tend to be more sensitive to frequency differences
between sounds, while species with trilled or buzzy song notes tend to
be more sensitive to time differences between rapidly repeated sounds.
These species differences may reflect evolutionary adaptations for
processing species-specific vocal communication signals. Finally,
compared to humans, Ken's research indicates that songbirds are less
sensitive to high frequency sounds, but more sensitive to time
differences between rapidly repeated sounds.