7 Millie Mine Bat Viewing Site 
wildlife viewing
| directions and facility information
 
Photo: Bill Scullon, MI DNR
All bats have a sophisticated sonar system
that allows them to capture flying insects in total darkness. Bats are
very beneficial to humans, consuming thousands of insects, many of them
considered pests, every night.
 
Bat Viewing Ssite and Buildling
theBat Cage
Photo l-r: Bill Scullon, MI DNR; David Kenyon,
MI DNR
The visible portion of this site is small
and inconspicuous—just the mouth of an abandoned iron ore mine that is
covered with a special steel grate. But what lies beneath the surface is
another story. A steep mine shaft drops 360 feet into the earth,
providing a roosting and hibernation chamber for bats. The mine entrance
is just a short walk from the site parking area. This abandoned mine is
just one of thousands that were created in the upper peninsula throughout
its rich mining history. Mine shafts opened in search of iron, gold,
copper, and uranium. Many mine shafts have been closed with rock, earth,
even old car bodies, to reduce their hazard to humans, but unfortunately,
also destroying their value to over-wintering bats. The special grate on
the Millie Mine prevents people from falling into its vertical shaft, yet
allows bats to come and go as they please. This is one of about 30 sites
that have been protected with similar bat entrance grates in the Upper Peninsula. It is the first one to be
developed as a bat interpretive site.
 Wildlife
Viewing
Bats on the cave ceiling
Photo: Bill Scullon, MI DNR
The Millie Mine is a critical hibernating
and breeding location for up to 50,000 bats—one of the largest known
concentrations of bats in the Midwest.
Big brown and little brown bats from all over the region
come here to hibernate during the cold winter months. They are
believed to migrate in from throughout the Great Lakes region–Wisconsin, Minnesota, Ontario,
perhaps even Michigan’s Lower Peninsula. Bats start arriving at the mine in
late August and early September. They remain in the mine shaft throughout
the winter and begin emerging in late April and May. Some use the mine as
their permanent home. Most, however, will fly back to their forested home
areas to spend the summer where they roost during the day under the bark
of dead trees or in other small crevices. The females will typically use
large hollow trees, abandoned buildings, or other human structures as
maternity roost sites where they raise their young with other females
during the summer. Males live a separate and more solitary life during
this time.
Bat festival
Photo: Bill Scullon, MI DNR
The best time to view bats is in September
and early October, right at dusk, as the bats begin to emerge from the
mine. They feed throughout the night and return an hour to half hour
before daylight. Local businesses cooperated with the Department of Natural
Resources and its Nongame Wildlife Fund to erect the steel cage over the
top of this mine and to develop it as a bat interpretive site. It has
become an area attraction, adding economic benefits to the Iron Mountain area. The site has been
host to a national bat festival that is held annually throughout the
country by Bat Conservation International. The festival attracted
thousands of participants when held at this wildlife viewing site.
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