Tagish Narrows (YK017)

Tagish Narrows (YK017)

Tagish, Yukon

Description du site

The Tagish Narrows consists of the Tagish River, and adjacent portions of Tagish Lake to the south and Marsh Lake to the north, located in southern Yukon. The river, which is about 7 km in length, is the focal point of the community of Tagish. The water stays open here longer in fall and earlier in spring because, in general, outlets for larger lakes, such as Marsh Lake, have higher velocity and turbulence of water flow. The area is also relatively shallow and narrow, allowing warmer water from deeper layers of the lake to mix with colder upper layers, thereby melting the ice. In April and May, water levels in both lakes are at their lowest, exposing extensive mud and sand flats and beds of aquatic vegetation. Residential development occupies much of the west shore and portions of the east shore of the river, and there is a bridge crossing near the north end.

Oiseaux

The Tagish Narrows is one of the most important waterfowl migration areas in the Yukon. It is one of three large lake outlets near Whitehorse that are heavily used by waterfowl and other waterbirds. In early spring migration, these areas reliably provide open water and food at a time when there are few other places for waterfowl to go. Trumpeter Swans are the most well-known and conspicuous spring migrants using the site. It is possible to see up to 1,000 birds at a time, representing about 5% of the global population. Each spring, it is estimated that several thousand individuals use the area. Over 20 species of waterfowl are found annually within the site, with an estimated total of at least 50,000 individuals recorded (most are found in the spring). Some of the more abundant duck species are American Wigeon and Green-winged Teal, and Canvasback.

Numerous other waterbirds use the area in spring, such as loons, grebes and various shorebirds. Maximums for spring migration include 40 Common Loon, 100 Red-necked Grebe, 120 Horned Grebe, and 313 Pectoral Sandpiper. Good numbers of land birds such as Horned Lark, American Pipit and Lapland Longspur migrate through the area in spring. Also, a variety of birds of prey are commonly seen in northward migration.

Enjeux de conservation

Parts of the east side of the Tagish Narrows have been indicated as a bird refuge notation on federal land maps. This carries no formal protection but ensures that the migratory bird interest is taken into account in formal land use decisions affecting the area. Much of the site is currently under consideration as a National Wildlife Area and a Migratory Bird Sanctuary.

Two downstream dams have changed the natural water levels at this site. Instead of high water peaking in mid to late summer and declining in fall, high water is being maintained from late summer until November for winter power generation. This means that fall use of the area by birds is less than it might formerly have been. Also, water contamination from septic systems and runoff is a potential issue. Birds are sometimes disturbed by off-road vehicles, boats, dogs, hunting, and other human activities, due to the close nature of urban infrastructure. Construction of power lines, reconstruction of a bridge over the river and a marina, have been some of the additional issues of concern in this area. Overhead utility lines on the highway bridge formerly posed a threat to flying birds but these were recently rerouted under the bridge deck at the request of concerned local residents.

Catégories ZICO Habitats Usages Menaces Potencielles ou Existantes Status de Protection

• Cygne trompette2 000 (max.)
• Bécasseau à poitrine cendrée1 700 (max.)
• Quiscale rouilleux54 (max.)
• Oiseaux aquatiques50 000 (max.)