Seven related aspects
of en route ecology receive quite a bit of our attention:
We
are currently collaborating with Dr. Nick Komar of the Arbovirus
Diseases Branch of the CDC, on a study investigating the
role of migratory birds as dispersal agents for West Nile
Virus. While migratory birds are considered one of
the primary sources of WNV in new regions, there is little
direct evidence of a bird's motivation and ability to migrate
while infectious (i.e. viremia titers capable of infecting
biting mosquitos). Our principal objective is to determine
if migratory birds with active WNV infections undergo normal
migratory behavior (i.e. display migratory activity and seasonally
appropriate migratory orientation). We are performing experiment
in both a field and laboratory setting.
What is the relationship between intrinsic
(within-habitat) and extrinsic (between-habitat) determinants
of habitat use during migration? How do migrants select
among alternative habitat types? What constrains choice?
What cues are used? What are the functional consequences
of differential use of en route habitat?
What factors (including endocrine)
mediate a migrant's response to variation in energetic requirements?
How plastic is the migrant's response to en route contingencies?
We are developing dynamic spatial models
that combine information on stopover ecology with GIS-based
map data to stimulate how patterns of habitat availability
(e.g., patch size, shape, distribution) affect migratory
birds at the individual and population level of analysis.
How do events during migration affect
the occupation of breeding/wintering habitat following migration?
What are the consequences of en route events for survival
during the "winter" and for reproductive performance during
the breeding season?
Individuals
with different levels of migratory experience can be expected
to respond differently to the exigencies of migration --
differences that may affect survival and reproductive success.
Likewise, we have every reason to believe that males and
females may adopt different migration strategies.
Although we are interested in asking
how migratory birds integrate sensory information,
such as geomagnetic stimuli and patterns of polarized
light,
to determine their migratory direction, current research
interests emphasize that orientation decisions are
made in an ecological context by migrants that vary in
their
nutritional condition. Orientation research is being
done
in collaboration with Swedish colleagues from Lund
University who have worked with us at study sites along
the northern
coast of the Gulf of Mexico.
