MClintock Bay and the Lewes River Marsh are located about 30 kilometres southeast of Whitehorse, in the Yukon Territory. The shallow MClintock Bay is at the north end of Marsh Lake; here the outflow of the Yukon River is adjacent to the inflowing MClintock River, which has a rich delta, mudflats and beds of submergent aquatic vegetation, including pondweeds. Three kilometres downstream along the Yukon River is the Lewes River Marsh, which consists of side channels, shallows, marshes and mudflats on both sides of the main channel.
This area is an important and high profile spring migration area for waterfowl; arguably southern Yukons most well known and most heavily used spring migration area. The outlets of certain lakes, such as this site, are the first open water available in the spring and are heavily used by birds wherever they coincide with shallow water and food. Globally significant numbers of Trumpeter Swans pass through in spring migration, with up to 1,500 birds (around 7.5% of the global population) being seen in one day. It is estimated that perhaps 6,000 birds (over a quarter of the global population) utilize the area in the spring. Their close relative, the Tundra Swan, can be seen in the area in even larger numbers, with peak one day counts approaching 2,000 birds (almost 2% of the western population) and estimated spring totals of over 12,000. Waterfowl are seen in globally significant numbers, with over 50,000 birds estimated using the site annually, most importantly in spring. Over 20 species of waterfowl stage or breed here - Northern Pintail, American Wigeon and American Green-winged Teal are some of the commonest species.
Shorebirds use the mudflats primarily during spring migration. A count of 1,800 Pectoral Sandpipers (almost 4% of the estimated global population), in MClintock Bay alone, on May 18, 1997, was one of the highest ever one-day counts recorded in the Pacific/Yukon region. Other shorebirds that have been seen in high numbers include Lesser Yellowlegs and Common Snipe.
Other birds in the area include nesting Bald Eagle and Herring Gull, and landbirds, such as American Pipit, Horned Lark, Rusty Blackbird, and Lapland Longspurs (1,000 plus on one day) which can be seen in high concentrations during spring migration.
BirdLife International (2020) Important Bird Areas factsheet: M'Clintock Bay to Lewes River Marsh. Downloaded from http://www.birdlife.org on 04/12/2020.