The Common Loon is strongly
dependent on lake food webs during the breeding season and thus is a
potential indicator of lake health. The Canadian Lakes Loon Survey (CLLS)
was initiated in 1981 by Bird Studies Canada (then Long Point Bird
Observatory), Environment Canada (Canadian Wildlife Service - Ontario
region), the Ontario Ministry of Natural Resources and other
co-operators. The CLLS continues to be a long-term project of Bird
Studies Canada and receives support from sponsors including the
Canadian Millennium Partnership Program, Canada Trust Friends of the
Environment Foundation, Canadian Wildlife Service - Ontario and
Atlantic Regions, Northern Reflections, North American Loon Fund,
Common Loon Resources (Gregory M. Nelson) and the donations and fees
of participants and supporters. The main goal of the CLLS is to
conserve and protect loons by increasing our understanding of loons
and human impacts on them. The CLLS coordinates volunteers in
monitoring Common Loon breeding productivity on Canadian lakes. The
data acquired by CLLS participants provide information on the effects
of acid precipitation, human disturbance and other factors on breeding
loons.
This report ("Temporal
Patterns in Breeding Success of Common Loons in Ontario,
1981-1997") uses indices of loon breeding success from the
Ontario portion of the CLLS database to accomplish several tasks:
- estimate the magnitude of
annual variation in loon breeding success
- re-evaluate the effects of
lake acidity on loon breeding success
- estimate the effects of
human disturbance on breeding success
- use these analyses to make
recommendations about the contribution of surveys of breeding
loons to future lake biomonitoring in Ontario
This report supports the
results of earlier studies that documented a lower average breeding
success for loon pairs on acidic lakes. The report indicates that loon
breeding success is low on even moderately acidic lakes. Surveyed
lakes below pH 6 appeared to become progressively poorer in their
ability to sustain loon chicks though six weeks of age.
Download the
Full Report (447 K PDF File; Adobe Acrobat Reader Required)
