Distribution, Abundance, and Status of the Greater Sage-Grouse, Centrocercus urophasianus, in Canada

Abstract

We reviewed the historic and present distribution of Greater Sage-Grouse (Centrocercus urophasianus) in Canada and found that the species has been eliminated from approximately 90% of its estimated historic distribution. Sage-grouse have been extirpated from British Columbia and reduced to remnant populations in Alberta and Saskatchewan. Estimates of the size of the population decline in Canada range from 66 to 92% over the last 30 years based on currently occupied habitat. As a result, sage grouse have been listed as Endangered in both Alberta and Saskatchewan by provincial governments and federally in Canada by COSEWIC. Intensive surveys from 1994 to 1999 in both provinces suggest that the 1999 spring breeding population had declined to between 813 and 1204 individuals. The number of active lek sites has continued to decline, suggesting that some habitats have become unsuitable to support viable sage-grouse populations. Number of yearling males recruiting to leks each spring has been low, suggesting that production and overwinter survival of young are the major problems related to the decline. Low chick survival rate, with only 18% surviving to 50 days of age, is the most likely parameter contributing to the population decline. These declines could be related to one or any combination of habitat changes, livestock grazing pressure, oil and gas developments, or climate change, all of which could lead to increased predation rates and decreased survival. It is questionable if the present population of sage-grouse in Canada is large enough to remain viable.