Nesting and Reproductive Activities of Greater Sage-grouse in a Declining Northern Fringe Population

In Canada, Greater Sage-Grouse (Centrocercus urophasianus) are at the northern edge of their range, occurring only in southeastern Alberta and southwestern Saskatchewan. The population in Canada has declined by 66% to 92% over the last 30 years. We used radio-telemetry to follow 20 female Greater Sage-Grouse and monitor productivity in southeastern Alberta, and to assess habitat use at nesting and brood-rearing locations. All females attempted to nest. Mean clutch size (7.8 eggs per nest) was at the high end of the normal range for sage-grouse (typically 6.6–8.2). Nest success (46%) and breeding success (55%) were within the range found for more southerly populations (15% to 86% and 15% to 70%, respectively). Thirty-six percent of unsuccessful females attempted to renest. Fledging success was slightly lower than reported in other studies. Thus, reproductive effort does not appear to be related to the population decline. However, chick survival to $50 days of age (mean 5 18%) was only about half of that estimated (35%) for a stable or slightly declining population, suggesting that chick survival may be the most important factor reducing overall reproductive success and contributing to the decline of Greater Sage-Grouse in Canada.