How many loons are there in Canada?
Canadians have always valued loons as symbols of wilderness. However, our enthusiasm for loons is not matched by a knowledge of their status or our impacts on them. Four of the world's five species of loons breed in Canada, but the abundance and even in some cases the geographical ranges of these species are still poorly known.
Loons are widely distributed across much of Canada, making it difficult and expensive to survey populations. There are extensive areas of the Arctic for which we know nothing about loon densities. Even when numbers of loons in localized areas can be determined, the suitability and abundance of loon habitat varies widely, making it difficult to arrive at reliable country-wide estimates of abundance.
How Many Common Loons?
The Common Loon is the species for which we have the most reliable information on population numbers, because of its southern distribution and its overlap with human populations. Common Loon populations in Canada have been estimated at between 250,000 and 500,000 individuals. This number is based in part on figures derived for various provinces. Provincial populations have been estimated at 1,000 breeding pairs in New Brunswick, 1,200 breeding pairs in Nova Scotia, 35,000 breeding pairs in Quebec, and 97,000 breeding pairs in Ontario. These figures range from shot-in-the-dark guesses to more accurate estimates based on Breeding Bird Surveys or aerial surveys.
Population trends of Common Loons are hard to determine due to lack of historical data. However, there are numerous anecdotal accounts of declines in the southern parts of the loon's breeding range in Canada over the past 100 years. These are supported by reports of reduced breeding success due to human development and recreational use of lakes, acid precipitation and other pollutants.
Nevertheless, Breeding Bird Survey results show an increase in Common Loons from 1966 to 1994, and no significant trends are evident in numbers of wintering loons in North America from Christmas Bird Count data collected between 1959 and 1988. No obvious trends in numbers of breeding pairs of loons were detected in Quebec between 1954 and 1979 nor determined from aerial surveys conducted in Ontario and southern Quebec between 1990 and 1995. So, it seems likely that if Common Loons have declined since pre-settlement times, most of that decline occurred before modern survey programs were implemented.
What About the Other Species?
Yellow-billed, Red-throated and Pacific Loons have been surveyed in Alaska but no reliable population estimates exist for Canada. Yellow-billed Loons are the least common and least studied of these three species, and the extent and locations of prime breeding habitats and the density of Yellow-billed Loons within that habitat are unknown. Estimates on Banks Island, range from 87 to 3,000 birds, a 34-fold difference in numbers! Alaskan Yellow-billed Loon populations have been estimated at between 2,400 and 3,500 birds, and numbers in North America have been roughly estimated to be less than 25,000. Population trends of Yellow-billed Loons are unknown.
Red-throated Loon Yellow-billed Loon
© Photos by: Ron RidoutEstimates for Red-throated and Pacific Loons are similarly uncertain. Populations of Red-throated Loons were estimated at 2,250 breeding pairs in Quebec and between 784 and 892 breeding pairs on the Queen Charlotte Islands, B.C. Numbers of Red-throated Loons in Alaska have been estimated at between 13,000 and 20,000 individuals in various reports. We know very little about Red-throated Loon numbers across the Canadian Arctic, the bulk of the species' North American range. Christmas Bird Count data collected between 1959 and 1988 reveal no significant trend in wintering Red-throated Loons in North America.
Estimates of Alaskan populations of Pacific Loons, based on extensive aerial surveys, range from 64,000 to 125,000 individuals. Some people consider the Pacific Loon to be declining in North America. However, the Alaskan population remained stable from 1977 to 1993 and Christmas Bird Count data reveal no significant trends in wintering Pacific Loons between 1959 and 1988.
In view of the difficulties of estimating populations of loons over large areas, perhaps the best approach is to survey representative areas of loon habitat and areas in which loons might be subject to direct negative effects of human activities. While aerial surveys will continue to be necessary to gather population information from remote areas, existing volunteer programs like the Canadian Lakes Loon Survey are well-suited to determine trends or the effects of human activities on loons.
- Harry Vogel
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Canadian Lakes Loon Survey
Bird Studies Canada
P.O. Box 160, Port Rowan, Ontario, Canada N0E 1M0
Tel: 519-586-3531 Fax: 519-586-3532
Questions about the CLLS? Please contact Kathy Jones aqsurvey@bsc-eoc.org
Photos copyrighted by Ron Ridout
