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Leslie Street Spit (ON038)


Leslie Street Spit (ON038)

Toronto, Ontario

Latitude 43,633°N
Longitude 79,329°O
Altitude ??m
Superficie 10,84km²

Description du site

The Leslie Street Spit extends from the Toronto shoreline about 5 km southwest into Lake Ontario. It is located immediately to the east of the Toronto Islands and Harbour. It is a human-made feature that includes both Tommy Thompson Park and the Endikement Area. Tommy Thompson Park consists of a main road and four peninsulas that were constructed from dredge spoil between 1972 and 1975. Construction of the Endikement Area began in 1980 and is continuing. The three cells, which are closed to the public, store contaminated dredge from the Toronto Inner Harbour. Much of Tommy Thompson is now covered with dense thickets of cottonwoods and willows that support an impressive number of Black-crowned Night Heron nests.


At least two species are regularly present on Leslie Street Spit in significant numbers: Ring-billed Gulls and Black-crowned Night Herons. The long term Ring-billed Gull breeding population on the spit averages about 55,000 pairs. This represents about 6.2% of the world's estimated breeding population, and as much as 9% of Canada's estimated breeding population. A peak of 75,564 pairs was recorded in 1984, which is 8.4% of the global population.

Nationally significant numbers of Black-crowned Night-Herons are also present with as much as 30% (1,195 pairs) of the estimated Canadian breeding population being recorded in 1996. The long term average from 1983 to 1997 is 612 pairs, or 15% of the national population. The population increase in the late 1980s may have been the result of colonization from nearby Muggs Island. A gull eradication program resulted in a substantial reduction in the gull colony on Muggs. It has been suggested that the lack of gull eggs and chicks as food for the night-herons, and the availability of good nesting trees and large numbers of gull eggs and chicks at Leslie Street Spit, prompted the shift. Common Terns were formerly present in significant numbers, but their populations have declined considerably in recent years (from a maximum of 1,694 pairs in 1982 to a minimum of 108 pairs in 1989). Double-crested Cormorants have recently colonized the site, starting in 1990 at 10 nests, and increasing to an average of 1,204 pairs from 1994 to 1998, including a peak of 1,727 nests in 1997.

In addition to colonial birds, large concentrations of migrating songbirds have occurred on Leslie Street Spit, such as 370 American Pipits in October, 1994. Other records of note include a flock of 200 Whimbrel during the spring of 1994, and a concentration of 34 Long-eared Owls during the winter of 1997.

Enjeux de conservation

The Leslie Street Spit is accessible to mammalian predators, and the colonies are subject to chronic disturbances by people and their dogs. Vegetation succession and predation by Ring-billed Gulls on eggs and young of other colonial species are also continuing problems. Numerous conservation measures have been taken, and others are in progress or have been proposed, including: vegetation control, control of Ring-billed Gull populations, reduction of human interference, creation of new nesting habitat, and control of mammalian predation on eggs and chicks.

Catégories ZICO Habitats Usages Menaces Potencielles ou Existantes Status de Protection
Goéland à bec cerclé
Nombre Année Saison
100 0002011Printemps
110 0001986Été
149 1281984Été
Quiscale rouilleux
Nombre Année Saison
25 - 462011Automne
30 - 622010Automne
30 - 362007Automne
Bihoreau gris
Nombre Année Saison
2 0002003Été
2 3901996Été
1 2241990Été
Harle huppé
Nombre Année Saison
4 0002010Automne
Grèbe jougris
Nombre Année Saison
430 - 7002014Printemps
Martinet ramoneur
Nombre Année Saison
60 - 1002017Printemps
30 - 802016Printemps
24 - 502015Automne
30 - 502015Printemps
35 - 2002014Printemps
50 - 2002013Printemps
25 - 282012Printemps
40 - 1502011Printemps
25 - 522010Automne
55 - 562010Été
25 - 502010Printemps
38 - 422009Printemps
29 - 2502008Printemps
Ictérie polyglotte
Nombre Année Saison
1 - 22012Printemps
1 - 22011Printemps
Moucherolle vert
Nombre Année Saison
Paruline de Kirtland
Nombre Année Saison
Paruline orangée
Nombre Année Saison
Pie-grièche migratrice
Nombre Année Saison
Râle élégant
Nombre Année Saison
Cormoran à aigrettes
Nombre Année Saison
15 0002017Automne
3 1961998Été
3 4541997Été
2 6321996Été
1 2221995Été
1 5361994Été