Field Notes (August 2010)
- Rod Steinacher
Not everybody likes them, some folks actually hate them, but it’s hard to deny the
value of bats to the environment. Bats consume huge numbers of insects (some
eat up to their own body weight in bugs each night!) … millions of pounds of
insects each year.
Bat populations in North America, and here on the Bruce, have a number of
pressures on them. Migrating south at night from August to October and
returning north in May, Red Bats and Hoary Bats (and now Silver-haired Bats), in
additional to all of the normal migratory stresses, are particularly susceptible to
being killed by wind turbines. With an increase in wind-produced energy, these
bats are also at increased risk. Research into bat migration patterns on the
Bruce Peninsula should help inform decisions on where to locate wind turbines in
the future.
Since 2006 in the USA, and the spring of 2010 in Canada, a new pressure on bat
populations has been identified. Called “white nose” syndrome, after the white
fungus found growing around bats’ muzzles, this often-fatal condition is being
found in an increasing number of bat caves in northeastern North America. The
fungus causes bats to awaken from hibernation, using up energy otherwise
needed for continued hibernation. This dooms the bats to almost certain death.
The condition can kill up to 90% percent of bats in a colony, and poses a huge
threat to bat populations in general. Some experts predict that the now common
Little Brown Bat may be extinct in as little as 20 years. We can expect an
increase in insect pests as bat numbers rapidly decline, with humans and
agriculture directly impacted by this dramatic change.
MNR Science Specialist Lesley Hale swabs the muzzle of a Northern Long-eared Bat to
test for the presence of “white nose syndrome”, which may cause some bat species to
go extinct in the near future.
Studies are currently under way on the Bruce to generate this important data and
to more clearly understand population trends. Lesley Hale, a Science Specialist
(Renewable Energy) with the Ontario Ministry of Natural Resources, and in
partnership with Bird Studies Canada, is currently resampling local bat
populations. Test mist netting of bats is currently underway at the Cabot Head
Research Station, and after only the first night (August 25/26) of monitoring, the
Silver-haired Bat has been confirmed as a species for the Bruce Peninsula.
Lesley will also visit local bat hibernacula, along with National Park staff, to check
for the possible presence of white nose syndrome. Future MNR plans for bat
studies on the Bruce include using radio telemetry tracking to more clearly define
bat migration routes.
At the same time, Rachel Hamilton, a Masters student with bat expert Brock
Fenton at the University of Western Ontario, is using acoustic monitors to
determine what area of the Peninsula bats are using for migration. As of this
date, four monitors have been set up, including one on the observation tower of
the National Parks Visitor Center and one in my yard at Cape Hurd. Rachel
hopes to have 16 monitors in place by next year; six along the Huron shore, six
down the center of the Peninsula, and six along the Georgian Bay shore. This
will require partnering with additional people and organizations on the Bruce.
Her hypothesis is that bats favour shorelines for migration, and that the center of
the Peninsula is not as fully utilized. If proven by her study, this may well have
implications for locating wind turbines.
Bat populations on the upper Bruce Peninsula were first studied by Sandy
Dobbyn during the summers of 1993 and 1994, as part of the “Bruce Peninsula
National Park Mammal Inventory” (July 1996). Six species of bats were captured
or identified during the study, using mist nets, Tuttle traps, and acoustic bat
detectors. In addition to the migratory species mentioned at the beginning of the
article, four other year-round resident species were also identified; the
uncommon Eastern Small-footed Bat, Little Brown Bat, which we commonly have
flying around our houses in the evening (at least for now), as well as Northern
Long-eared Bat and Big Brown Bat. They begin hibernation some time in
October and usually reemerge in May. Of the six species found in the area
during the study period (and now seven species with the confirmation of Silverhaired Bat), Little Brown, Big Brown, and Red Bats were the most wide spread.
Many people appreciate having bats around, both for their incredible dusk flights
and for their work as a natural insecticide and can be encouraged to stay in the
area by erecting one or more bat boxes. Many designs exist, and most work
well. Despite folk legend, bats do not want to get into your hair, and if trapped in
a building they just want to get out. Don’t take their frantic flight personally! We
need bats, even if they are not everyone’s favourite animals!
Further information:
1.
about white-nose syndrome in Canada, and about bats in general:
http://www.cwf-fcf.org/en/resources/online-articles/news/wildlife/white-nose-batsyndrome.html
and
http://news.nationalgeographic.com/news/2010/08/100805-bats-whitenose-fungus-extinction-science-environment/
2.
“Bruce Peninsula National Park Mammal Inventory” (July 1996):
http://www.castlebluff.com/bffscience/Bibliography/%5b178%5dBPNP_Mammal_
Inventory_Volume4_Final_Report.pdf
3.
bat research by Brock Fenton at University of Western Ontario:
http://www.science.ca/scientists/scientistprofile.php?pID=350
4.
bat box plans:
http://www.eparks.org/wildlife_protection/wildlife_facts/bats/bat_house.asp