Old Wives Lake is a large shallow saline lake located 35 km southwest of Moose Jaw, Saskatchewan. The Wood River, spring runoff, and seasonal rains provide the water sources for this lake; in severe drought years it has been known to be completely dry. Seasonal fluctuations in water levels result in the development of extensive mudflats, and exposed islands. On the eastern side of the lake a sandy, rocky island known as the Isle of Bays. It is located about 5 km from shore. Frederick Lake is a small basin located adjacent to the southwest shore of Old Wives Lake. Ducks Unlimited installed a dam on the Wood River at the west end of the lake, creating a large riparian marsh upstream, and a variable sized and very diverse marsh downstream; the rest of the lake has very little emergent vegetation.
During spring migration, Old Wives Lake supports significant numbers of migrating shorebirds. During the spring of 1987, a one-day aerial survey yielded a total of 64,392 shorebirds at Old Wives Lake. Surveys during the spring of 1993 and 1994 also yielded large numbers 32,706 and 37,755 respectively. Sanderlings and Baird's Sandpipers are two of the most abundant species. Although lake specific estimates are not available for all species (totals for Chaplin Lake and Old Wives Lake were often combined) the numbers are truly impressive: the three-year average for Sanderlings is 55,471 birds on both lakes (about 30% of the estimated North American population); for Baird's Sandpipers, an estimated 29,862 were recorded in 1987 on both lakes (as much as 40% of the world's population); for Semipalmated Sandpiper the two-year average is 29,600 (possibly 1% of the worlds population); and for Stilt Sandpiper, 9,000 individuals were recorded at Old Wives Lake in 1995 (9% of the worlds estimated population). Finally, American Avocet has been recorded in numbers as high as 1,577, which is over 2% of their national population.
The Lake is also important for nesting Piping Plovers, a nationally endangered and globally vulnerable species. In 1991, as many as 42 adults were recorded (about 3% of the Canadian Great Plains population during that year. Numbers in subsequent years have fluctuated with 12 plovers being present in 1993, 27 being present in 1994, and 8 being present in 1996.
Several colonial waterbirds also nest in significant numbers: American White Pelicans are the most conspicuous (an average of 1,933 nests 7 surveys between 1970 and 1991 about 3.5% of the estimated Canadian population) along with Double-crested Cormorants (an average of 336 nests 6 surveys between 1970 and 1991). During the breeding season about 3,000 Franklins Gulls have been recorded at the lake (just under 1% of the estimated population), along with numerous Ring-billed Gulls, California Gulls, and Common Terns. Large numbers of waterfowl also make use of this lake as a summer moulting area (> than 20,000 on a regular basis). In the mid-1980s as many as 63,000 moulting Canvasbacks were recorded at this site (about 10% of the estimated population).
BirdLife International (2020) Important Bird Areas factsheet: Old Wives-Frederick Lakes. Downloaded from http://www.birdlife.org on 28/02/2020.