Southern Ontario Bald Eagle Monitoring Project
The Southern Ontario Bald Eagle Monitoring Project, initiated
in 1983, is a cooperative venture of the Ontario Ministry of
Natural Resources, Canadian Wildlife Service, Bird Studies
Canada, community organizations, landowners, and volunteers.
Every year, landowners and volunteer nest monitors collect
valuable data on Bald Eagle nesting chronology, activity and
productivity, which allows biologists to monitor the health of
From 1983 to 1999, Bald Eagle nests were accessed and eaglets
were weighed, measured, and banded. Blood and feather collection
was added to the protocol in 1990 in order to monitor levels of
contaminants and heavy metals. Data collected from these field
studies showed that by the mid-1990s, levels of contaminants had
declined dramatically from historic highs. Coincident with the
decline in contaminants, the number of active nests and the
number of young produced at each nest increased, and the general
health of the Great Lakes Bald Eagle population improved. In
2004, the satellite-tracking program
was initiated with the goal of tracking the movements of
juvenile eagles in their first three to five years of life.
Every year the number of active territories and nests slowly
increases. During the last five years, nesting productivity has
stabilized at 1.4-1.5 fledglings per active nest, which is
likely sufficient to maintain a stable population. Currently,
most of the Bald Eagle nests in southern Ontario are located
along the north shore of Lake Erie, though they are starting to return to the shores of Lake Ontario.
Future prospects for the recovery of Bald Eagles in southern
Ontario are positive, but there are enduring concerns about the
long-term viability of the population. Bald Eagles in southern
Ontario appear to have shortened lifespans compared to other
populations, possibly due to heavy metal poisoning. In the last
few years, several Bald Eagles found dead in Ontario have had
elevated levels of both mercury and lead in their bodies.
Long-term exposure to such contaminants can limit eagles'
reproductive capabilities, alter their behaviour, impair their
foraging abilities, increase their susceptibility to disease,
and even cause death. Determining whether heavy metal exposure
is a long-term problem that is responsible for decreased
longevity is one of the main issues that the Southern Ontario
Bald Eagle Monitoring Project is now investigating.
How Can You Help?
BSC needs volunteer Citizen Scientists to participate in a
number of conservation-related projects, including Bald Eagle
nest monitoring. To become a member of BSC and support wild bird
conservation, contact us toll-free at 1-888-448-BIRD. As a
member, you will receive updates on all of our regional,
national, and international programs, and you will have
opportunities to volunteer for various programs.
The Bald Eagle program also accepts donations, or you can
eaglet . Bird Studies Canada is a registered charity, and
tax-deductible receipts will be issued for all donations of $10
Bald Eagles are a Species at Risk in Ontario, so anyone who
encounters an injured or dead Bald Eagle should contact Bird
Studies Canada or their local MNR office immediately (prior to
taking any bird into their possession) for instructions on how
To report a sighting in your area, or for more information on
the Southern Ontario Bald Eagle Monitoring Program (including
how to become a volunteer or make a donation), please contact:
Biologist & Science Educator
Bird Studies Canada
PO Box 160
Port Rowan, ON