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Location Canada, Alberta
Central coordinates 111o 50.02' West  50o 3.66' North
IBA criteria A4i
Area 1,000 ha
Altitude 0
Year of IBA assessment 2008

Bird Studies Canada/Nature Canada

Site description Hays Reservoir is located about halfway between Medicine Hat and Lethbridge in southern Alberta. It is an artificial reservoir with five small islands that are used by colonial nesting birds. The reservoir contains little marsh development, but it is surrounded by native mixed grassland habitat. An irrigation canal feeds the reservoir. The nationally vulnerable Great Plains Toad was reported breeding at this site in 1982.

Key Biodiversity Hays Reservoir supports a globally significant breeding population of American White Pelicans. In 1998, 3,850 nests were recorded at the reservoir. This number is over 4% of this species global population and the colony is the largest in Alberta.

Several other colonial waterbird species also nest in the reservoir. It supports one of the largest Ring-billed Gull colonies in Alberta (5758 nests in 1998). In 1998, 328 Double-crested Cormorant and 228 California Gull nests were counted. Black-crowned Night-Herons and Common Terns nest here, as do Caspian Terns on rare occasions - in 1998, one nest was found.

In addition to colonial waterbirds, this site is an important staging, moulting and production area for waterfowl, such as dabbling ducks, diving ducks and geese. The reservoir also provides habitat for migrating shorebirds.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
American White Pelican Pelecanus erythrorhynchos breeding  1998  3,850 nests  A4i  Least Concern 


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Freshwater lakes and pools  -

Land use

Land-use Extent (% of site)
water management major

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Hays Reservoir. Downloaded from on 22/10/2016

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