Michigan has more
than 3,200 miles of coastline - more than any state
in the lower 48. While this coastal zone is a place
of unique biological richness, it is also a place with
heavy human demands. We studied migration along the
northern Lake Huron shoreline in the Hiawatha National
Forest, an area celebrated for its concentrations of
passage and breeding migrants.
As Aldo Leopold
pointed out some 50 years ago in one of his essays from
Round River,"One of the fastest-shrinking categories
of wilderness is coastlines. No single kind of wilderness
is more intimately interwoven with history, and none
nearer the point of complete disappearance."
At the Lake Huron study
site, we conducted mist-netting,
insect sampling and focal observations of foraging
We also located and monitored American Redstart nests,
taking data on distance from the lakeshore, nest placement,
clutch initiation date, and number and mass of eggs
and nestlings. We sampled vegetation and insect
abundance within individual redstart territories.
Our situation is unique in that we were able to assess
lakeshore habitat as both a stopover site for migrants,
and a breeding site for those that stay.
here for a complete table
of all the birds captured at the Lake Huron
study site over the years.
summary report for 1999
summary report for 2000
Rob found that midges may be
especially important during early spring, when the first migrants
are beginning to arrive. A number of bird species gain
mass during this period; a time when few arthropods, outside
of midges, are available. Midges seem to feed both birds
and spiders, and spiders and midges seem to feed birds during
this early period. Thus, areas adjacent to northern Lake Huron
provide important stopover habitat for spring migrating landbirds.
Further, emergent aquatic insects are an important resource
for landbirds migrating through Michigan's eastern Upper Peninsula.
Both arrival timing
and arrival condition appeared to influence fitness in American
Redstarts. Redstarts arrived in northern Michigan with fat
stores, which may have been important as insurance against
poor weather typical of early spring. Further, both arrival
timing and arrival fat appeared to influence seasonal reproductive
performance. Early females initiated clutches early and produced
heavier nestlings. Early males appeared to settle on higher
quality territories and hatched nestlings sooner than later
arrivals. Finally, both females and males arriving with fat
experienced gains in reproductive performance as shown by
increased clutch size, egg volume and nestling mass. Rob's
results have implications for understanding how events occurring
during one phase of the annual cycle influence survival and
reproductive performance in subsequent phases. Migrants that
do well en route arrive at breeding grounds in superior condition,
which may contribute to survival and reproductive performance.
University of Southern Mississippi. Last modified:
24 February, 2007