Shallow Bay, Big Slough and Swan Lake

Country/territory: Canada

IBA criteria met: A4iii (2008)
For more information about IBA criteria, please click here

Area: 5,700 ha

Birds Canada / Nature Canada

Site description (2001 baseline)
Shallow Bay, Big Slough, and Swan Lake are located at the southwest end of Lake Laberge, in the Yukon Territory. Lake Laberge is a large (50 by 5 km) lake oriented roughly north-south, that is about 30 km north of Whitehorse. Shallow Bay is a shallow lake located 2 km west of the Yukon River inflow and connected to Lake Laberge via a 400 m channel which varies from a trickle at low water to a broad expanse at high water. Big Slough is a 4.5 km oxbow located on the Yukon River four kilometres upstream from its inflow to Lake Laberge. Swan Lake is a lake and adjacent 13 sq. km fen complex located two km east of the Yukon River, draining north into Lake Laberge via Laberge Creek, 2 km east of the main Yukon River Inflow. The Yukon River inflow to Lake Laberge consists of a large expanse of seasonally exposed sand and mudflats with braided channels. Marsh vegetation and extensive willows border much of the shore.

Key biodiversity
In April and May, Shallow Bay is one of southern Yukons best sites for waterfowl viewing. In the spring, the site does not open as early as do the lake outlets, but when there is an early spring, as in 1994, it gets very high use by waterfowl. The Pacific Coast population of Trumpeter Swans pass through here during spring migration in globally significant numbers. On April 18, 1994, a tally of 200 was made, which represents at least 1% of the global population. Other waterfowl, such as Tundra Swans (600 in April 1994), American Wigeons, scaup, and scoters, also stage here during migration. In general, the area is important to waterfowl in both spring and fall. The total number of waterfowl using the site in spring, summer (breeding and moulting), and fall is somewhere between 50,000 and 100,000 birds, which are globally significant numbers.

A record of 1,050 Mew Gulls during spring migration is significant, representing over 2% of the North American population. Other gulls can be fairly numerous, with 320 Herring Gulls reported in late June, 1998. Some passerines can be observed in high numbers during migration, such as Lapland Longspur - 1,000 were recorded on May 7, 1994. Snow Buntings can be seen in the hundreds, especially during fall migration. Also, this is one of the few places in the region known to host concentrations of loons, with up to 150 (Common, Red-throated or Pacific) being seen staging in spring at the Yukon River inflow to Lake Laberge.

At least 65 species of birds have been confirmed breeding at the site including Mallard (20 pairs), Northern Pintail (2 pairs), scaup (5 pairs), Barrows and Common Goldeneye (5 pairs), Wilsons Phalarope (1 family) and Short-billed Dowitcher (1 family).

Over 157 species of birds have been sighted at Swan Lake to date. Significant high counts of spring and fall migrants include 550 American Green-winged Teal (September 24, 1977), 430 Mallard (October 25, 1987), 525 American Wigeon (May 7, 1986), 350 Surf Scoter (May 15, 1983) and 500 Lesser Yellowlegs (May 13, 1984).

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Shallow Bay, Big Slough and Swan Lake. Downloaded from on 09/12/2023.