Quidi Vidi Lake lies within the city limits of St. John's, Newfoundlands capital city. Oriented northeast to southwest, the lake is cigar-shaped, with maximum dimensions of 1,600 by 350 m. The lake is fed from the north by the Virginia River and from the west by Rennies River. The eastern end of the lake empties into the ocean at the Quidi Vidi Gut. The lake shoreline is comprised of gravel and there are no islands, significant points, or emergent vegetation within the lake. From May to December, the lake is used for recreational boating.
Large numbers of gulls use Quidi Vidi Lake as a day time resting site in the late fall, winter and early spring when there is ice on the lake. At least five species occur in significant numbers (i.e., greater than 1% of their estimated North American populations). These species include: Herring Gull (10,000 as much as 2.8% of the estimated North American population); Great Black-backed Gulls (8,000 as much as 6% of the estimated North American population); Iceland Gull (2,000 as much as 6.6% of the estimated North American population); Glaucous Gull (750 about 1% of the estimated North American population); and Common Black-headed Gull (75 the largest wintering concentration in North America). All of these estimated are based on one-day high counts averaged over several seasons; it is likely that the total number of birds using the site is much larger.
The gulls do not feed at Quidi Vidi Lake except for the few dozen, mostly Herring Gulls, that steal bread from handouts to the ducks. The Herring, Great Black-backed and Glaucous Gulls use the dump as the main food source. Iceland Gulls feed at sewer outflows in St. Johns harbour and one sewer outlet in Quidi Vidi Gut. Iceland Gulls also feed along the coast on more natural food sources. Fifteen species of gulls have been seen at Quidi Vidi Lake with up to ten species present at one time. This site has a worldwide reputation for gull watching. The abundance, diversity and ease of observing gulls at Quidi Vidi Lake has attracted gull watchers from the Netherlands, Ireland, the United States, and the rest of Canada. Other birds commonly recorded at this site include: American Black Ducks (300), Mallards (25), Northern Pintails (50), Ring-billed Gulls, Mew Gulls, and Lesser Black-backed Gulls.
BirdLife International (2022) Important Bird Areas factsheet: Quidi Vidi Lake. Downloaded from http://www.birdlife.org on 09/08/2022.