Status of colonial waterbirds nesting in southern Manitoba

The southern Manitoba nesting abundance, colony location, historic present regional and provincial status of 12 colonial nesting waterbird species have been assembled, with major field data collected in 1979. American White Pelican (Pelecanus erythrorhynchos), Double-crested Cormorant ( Phalacrorax auritus, and Ring-billed Gull (Larus delawarensis ) breeding populations were at or near historic peaks with cormorant and pelican numbers larger than recent estimates for all of Canada. Eared Grebe (Podiceps nigricollis ), and Western Grebe (Aechmophorus occidentialis ) populations were considered in decline as were Common Tern (Sterna hirundo ) and Caspian Tern (Sterna caspia ) numbers. Management should include stronger protective measures, public education, colony habitat management, and monitoring of known and suspected colony locations. Human encroachment, pesticides, marsh draining, water-level manipulation, and disturbance are major threats to all Manitoba waterbird species.