Time for Nature

The common loon under surveillance

June 28, 2005

The development of recreational areas around lakes has significantly reduced reproduction of the common loon south of Canada.
© Parks Canada / J. Pleau

Although the loon is not an endangered species in Canada, the ever-increasing development of resort areas has significantly reduced its breeding area. In fact, shoreline development and increased human activity have eliminated numerous nesting sites. The loon needs a calm and quiet setting to breed. The acidification of lakes , as well as the presence of mercury in the fish it eats, also hinder its ability to breed.

La Mauricie National Park of Canada ensures complete protection of its habitat. However, this species is affected by the presence of fishermen, canoers and canoe-campers as well as the effects of air pollution. The loons in La Mauricie National Park have been under surveillance since 1987, which helps researchers get a better idea of what the future holds for all loon populations in Canada .

Acidification of lakes

To raise its young, a loon couple needs a significant quantity of small fish, close to 463 kg. Within this context, the reduced number of fish due to acid rain compromises the species' successful reproduction. The park is not immune to this threat, and 15% of the lakes have a pH level below 5.5 (i.e. are acidic). Of the 32 bodies of water where loons continue to nest, 12 are becoming acidified (pH between 5.5 and 6).

Mercury contamination

In 1997, the Park also participated in an extensive North American study conducted by the Canadian Wildlife Service . Its aim was to determine if the common loon accumulated enough mercury for it to have an impact on its survival or reproduction. The loons in La Mauricie National Park have one of the highest mercury concentrations in North America. One in four is faced with serious health, reproductive or survival risks. Since 40% of this species' area is contaminated with mercury, it is important that the presence of this toxic substance as well as its effects on these birds be monitored. This study is part of a loon monitoring program across North America (North American Biomonitoring Program). The aim of this program is to collect and share information on mercury contamination, allowing the comparison of results between regions.

Nesting in peace

During the nesting period, adults are very sensitive to human disturbances. The protection of nesting sites is essential.
© Parks Canada / J. Pleau

In the late ‘80s, La Mauricie National Park started taking measures to minimize conflicts between visitors and the loons . This was soon after the park biologists discovered that the breeding success of 20 couples had significantly diminished.

The park launched an awareness-raising program for the public. First, the use of motorboats was forbidden. Regulations were also implemented to ban canoers from stopping on the islands. As well, during the nesting period, access to certain lakes is forbidden to fishermen and canoers. In fact, the opening of the fishing season was delayed on some lakes to reduce the human presence when nests were being built. Traffic was reduced on other lakes through closing of canoe-camping sites and reducing the number of fishermen. As the loons were swallowing and being poisoned by lead fishing sinkers and jigs, they have been banned since 1997.

The protection of certain nesting sites has also been increased through floating warning signs. Lastly, rehabilitation of the park's islands is underway, and floating marshes for nesting have been created in a few places. These efforts have proven fruitful, since the loons have started nesting again on three of the lakes they had abandoned in 1980.

Being part of the solution

The park launched an awareness-raising program for the public, forbidding access to certain lakes during the nesting period.
© Parks Canada / H. Massé

This worrying situation led to the creation of the Canadian Lakes Loon Survey , a project that uses volunteers to monitor loons on Canadian lakes. The Better Lakes for Loons campaign provides cottage owners and other recreational users of these bodies of water with tips for contributing to loon conservation .

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