Introduction
    Drainage Basin Characteristics
    Lake Basin Characteristics
    Water Quality
    Biological Characteristics (Introduction)
    Biological Characteristics (Plants)
    Biological Characteristics (Invertebrates)
    Biological Characteristics (Fish)
    Biological Characteristics (Wildlife)
    References

Biological Characteristics (Wildlife)

Wildlife

A specific objective for many visitors to Alberta's lakes, and an added attraction for others, is the opportunity to observe wildlife in its natural habitat. Whether it is the plaintive cry of a loon on a boreal lake, the winnowing of snipe in a marshland, the spectacular dive of an Osprey, the wobbling parade of newly-hatched ducklings, or the silent passage of a muskrat, the sight or sound of wildlife adds immeasurably to an adventure at one of Alberta's lakes.

Alberta stretches from glacier-capped peaks in the west to the boreal forest of the north, through lush rolling farmland to arid flat prairie in the south. The diversity of terrestrial habitats is fascinating; similarly, the diversity of habitats in and around Alberta's lakes is equally impressive. Habitats in or near lakes provide a transition from water to land and there is usually a wide diversity of habitats and wildlife in a relatively small area. Some of the habitat types that develop within or near lakes and reservoirs include expanses of deep open water, shallow marshy wetlands in bays, shoreline mudflats, sand-gravel beaches, and islands of varying size and character. Just back from the shore area, there is often a zone of sedges and willows or bog, then relatively undisturbed bush or forest.

The deep, open-water habitat supports various fish species which are an important source of food for Ospreys, Bald Eagles, Common Loons, Common Mergansers, White Pelicans and Double-crested Cormorants (Fig. 60). River otters feed in areas where open water is close to the shore, especially where there are numerous islands or connecting channels between lakes. In the spring and fall, large expanses of open water provide important staging (resting and feeding) areas for migratory ducks and geese. Most of Alberta's large lakes include this kind of habitat; examples can be found at Beaverhill, Gull, losegun, and Athabasca lakes, and at St. Mary Reservoir.

Shallow areas in lakes and associated marshy wetlands support numerous and diverse species of plants and small organisms which provide shelter and food for many wildlife species. These areas provide habitat for over a dozen species of ducks, Canada Geese, Trumpeter Swans, Franklin's Gulls, several species of grebes, American Bitterns, muskrats and beaver (Fig. 61, Fig. 62). Small fish that live in these areas, such as stickleback and fathead minnows, are the prey of Great Blue Herons (Fig. 63), Belted Kingfishers, Black Terns, Western Grebes and mink. Moose come to feed on pondweeds and other aquatic vegetation in many lakes in the foothills and northern Alberta (Fig. 64). The marshy areas of a lake and parts of the littoral zone where aquatic macrophytes grow densely also provide habitat for several species of frogs (Fig. 65). The shallow areas of two lakes in southern Alberta, Tyrrell Lake and Crawling Valley Reservoir, provide habitat for tiger salamanders. The salamander populations in these lakes are thought to be neotenic, a condition in which mature salamanders retain larval characteristics such as external gills. This variant is not common in Alberta. Emergent vegetation such as common cattail and bulrush also provide nesting and feeding habitat for numerous types of small perching birds such as Redwinged and Yellow-headed blackbirds and Long-billed Marsh Wrens. Almost all of Alberta's lakes have examples of this habitat. Notable examples are found in Hastings, Moose, Gull and Driedmeat lakes.

Some lakes have shorelines of exposed mudflats or sand and gravel. These areas provide feeding, resting and, in some cases, nesting habitat for more than two dozen species of shorebirds that are found in Alberta. Some of these species, such as Killdeer, Spotted Sandpipers, Lesser Yellowlegs (Fig. 66) and Willets stay and nest, whereas others, such as Pectoral Sandpipers, Sanderlings, Dunlins, Ruddy Turnstones and American Golden Plovers are spring and fall migrants that rest and feed on their way between their breeding areas in the Arctic and their wintering grounds in the southern United States and Central and South America. A good example of this habitat can be seen on the shores of Beaverhill Lake. Lake Newell, Eagle Lake and Glenmore Reservoir also have some areas of good shorebird habitat.

Some lakes have islands, which can be small or large, forested or relatively bare. Islands provide secure nesting sites for White Pelicans (Fig. 67), Canada Geese, Double-crested Cormorants, Common Loons, Common Mergansers, and gulls. Because islands are often free of large predators like coyotes, populations of mice and voles sometimes increase unchecked and reach very high densities. Examples of islands used by wildlife can be found in Lac La Biche and Buffalo, Island, North Buck and Miquelon lakes, and in Milk River Ridge and Little Bow Lake reservoirs. These islands often represent the last nesting refuge for uncommon or rare species. To protect wildlife, islands should not be visited or even approached during the breeding season.

Often an area of sedges and willows develops a short distance from a lake. Here the soil is usually too wet to support larger trees or agricultural crops, but it is a zone of abundant wildlife. Marsh hawks nest in the tall grass or low shrubs and can be seen flying low over the marsh, seeking voles, frogs and insects. Short-eared Owls nest on the ground in these areas and can also be seen as they prefer to hunt in the day. American Kestrels, commonly called sparrow hawks, are often seen resting on poles or wires near marshes. Common Nighthawks perform their aerial acrobatics in the evening as they pursue insects. As darkness approaches, bats such as the little brown bat and big brown bat flit over the meadow and marshes. If forests grow near the lake, Merlin and Long-eared Owls might also be seen, as well as a wealth of warblers and other songbirds.

Artificially constructed reservoirs, particularly those with deep, open water, can provide areas valuable to some wildlife. Most reservoirs are built to store water when it is available and to release it when demand is high-usually in winter for electric power generation or in midsummer for irrigation. The wide range of water level fluctuations that results from this operation inhibits the establishment of a productive wetland/marsh habitat. Also, low water levels in winter or winter drawdowns cause serious freezing problems for muskrats, beaver, mink and otters. There are, however, two notable examples of reservoirs in southern Alberta in which the operation has been modified to provide excellent wetland habitat in a region where water is very scarce. The Tyrrell-Rush lakes complex is the first completed Wetlands for Tomorrow project in Alberta, and the recently built Crawling Valley Reservoir includes sub-impoundments, which promise to provide excellent habitat for muskrats and nesting waterfowl.

Lakes and reservoirs in Alberta are also valuable to terrestrial wildlife because the lake is often a focus for a park where land is preserved in its natural state and wildlife habitat is protected from encroaching agriculture or development. Most of Alberta's provincial parks are near or surround lakes - Crimson, McLeod and Dillberry lakes, to mention only a few. One of the province's largest urban parks, Glenmore, surrounds Glenmore Reservoir in the city of Calgary. The relatively undisturbed area around lakes and reservoirs often provides an oasis for wildlife such as deer, moose, bears, coyotes, badgers and a wide variety of owls, hawks and songbirds.

Readers interested in the wildlife at a specific lake may find more information by consulting the two guides written by the Finlays, or by contacting Fish and Wildlife Division, Alberta Recreation and Parks and local natural history associations. Common names of birds and mammals have been used throughout the Atlas; a list of common and specific names is given near the end of the Atlas.

J.M. Crosby and H.A. Stelfox