Sharp-tailed grouse «Tympanuchus phasianellus» in a resource development area at the northern edge of the species' range

The reproductive phenology and habitat requirements of sharp-tailed grouse (Tympanuchus phasianellus) are not well understood. Northern populations of sharp-tailed grouse (STGR) belonging to the Tympanuchus phasianellus caurus subspecies are particularly under-studied. Although the caurus subspecies is thought to be stable, beyond anecdotal sightings, little is known regarding STGR status or habitat requirements and tolerance to disturbance in the northern parts of its range. The present study focuses on a STGR population located in North-Central Yukon in and around the Klondike Goldfields. Female STGR were fitted with radio transmitters and monitored during the reproductive period over three study years (2015-2017) to quantify habitat use around identified lek sites during the nesting and brood-rearing periods, analyze the habitat selection of nesting and brood-rearing hens, and assess habitat effects on hatching and fledgling success. Among 41 radio-collared hens, nearly all attempted to nest (96.4% ± 2.5) and clutch size averaged 8.3 ± 2.1. Overall apparent nest success for all nests was 76.4% ± 1.9 (n = 39). Nest sites were situated where a shrub layer provided vertical cover and abundant bunchgrass understory provided horizontal cover. Survival was higher for early hatching nests in sites with fewer hummocks than later hatch nests with many hummocks. Brood rearing hens selected for habitats with mesic vegetation such as scrub birch and sedges, but also showed a preference for sites classified as dry rather than wet. Brood failure occurred less often within low elevation, sloping sites with abundant deadfall cover and more often within sites on south and east facing slopes with less deadfall. During both the nesting and brood rearing periods, hens did not select for shrub dominated sites equally; those with shrubs less than 2m in height were preferred over taller shrubs and avoidance increased as the successional stage progressed to maturing forest. Home range sizes (163.0 ± 52.9 ha, using 95% kernel density) were larger and distances traveled from the nest site to brood rearing habitat (1119.2 ± 187.9 m) were longer than previously described for STGR and other prairie grouse. Hen survival in the Klondike Goldfields during the reproductive period was 64.2% ± 6.2 (n = 70), with most mortality occurring during egg laying and incubation. The current research has helped advance our understanding of the phenological events, space use and habitat selection of an isolated populations of a lekking bird species in a resource development region, and characterize the importance, scale, and inter-relatedness of three major impacts - mining activity, fire history, and predators – on STGR survival and reproductive success in the Klondike Goldfields

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