Like many other birds of prey, osprey (Pandion haliaetus) populations declined due to pesticide use in the mid-1900s. Populations rebounded during the latter part of the 1900s. The first study of osprey in Yellowstone National Park occurred in 1917 by M. P. Skinner, the park’s first naturalist. It was not until 1987 that the Yellowstone National Park bird program began monitoring breeding osprey annually, although an extensive survey on reproduction, diet, and habitat was conducted during the 1970s.
Since monitoring began, Yellowstone’s population of osprey has been considered relatively stable. On average, 50% of nests succeed (produce young) each year, with each successful nest producing an average of one to two young.
Ospreys are surveyed via fixed-wing aircraft and by ground-based surveys from May through August. During the survey flights, the majority of nests are monitored for occupancy and breeding activity. In addition, all suitable lakes and rivers are surveyed for potential new territories and nest sites.
Number in Yellowstone
A recently completed study conducted by park biologists found a significant relationship between the declines in cutthroat trout and osprey reproduction at Yellowstone Lake. Recent increases in the number of young cutthroat trout caught by the Yellowstone fisheries program during the fall netting assessment are encouraging. An increase in cutthroat trout production may lead to an increase in nesting pairs of ospreys and improved nesting success at Yellowstone Lake.
Songbirds and Woodpeckers
Passerine and near passerine species comprise the majority of bird species in Yellowstone.
Annual Bird Program Reports. National Park Service, Yellowstone National Park. https://www.nps.gov/yell/learn/nature/birdreports.htm
Baril, L.M., D.W. Smith, T. Drummer, and T.M. Koel. 2013. Implications of cutthroat trout declines for breeding opsreys and bald eagles at Yellowstone Lake. Journal of Raptor Research 47(3): 234–245.
Poole, A.F., R.O. Bierregaard, and M.S. Martell. Osprey. The Birds of North America Online. https://birdsna.org/Species-Account/bna/species/osprey/introduction
Last updated: May 6, 2019