Productivity of Ospreys, Pandion haliaetus, Affected by Water Levels Near Loon Lake, Saskatchewan, 1975-2002


  • C. Stuart Houston 863 University Drive, Saskatoon, Saskchewan S7N 0J8
  • Frank Scott Box 2, GS 317, Saskatoon, Saskatchewan, S7K 3J6
  • Rob B. Tether Department of the Environment, Unit 1, 101 Railway Place, Meadow Lake, Saskatchewan, S9X 1X6



Osprey, Pandion haliaetus, clutch size, nest success, artificial nest structures, lake water levels, fish populations, Saskatchewan


Between 1975 and 2002, diminished breeding success of Ospreys was associated with drought and falling lake levels in the western half of our study area near the town of Loon Lake, west-central Saskatchewan. Only 46% of nest attempts were successful in the west compared to 72% in the east, producing 0.88 young per accessible nest in the west and 1.42 in the east. Breeding success was greater in the eastern half, where water levels were stable, in spite of increased human use of the resort lakes there. Our unique long-term Canadian data base results support Ogden's 1977 prediction that Osprey productivity may decrease when water levels drop and fish populations are reduced.