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We revised distribution maps of potential presettlement habitat and current populations for Greater Sage-Grouse (Centrocercus urophasianus) and Gunnison Sage-Grouse (C. minimus) in North America. The revised map of potential presettlement habitat included some areas omitted from previously published maps such as the San Luis Valley of Colorado and Jackson area of Wyoming. Areas excluded from the revised maps were those dominated by barren, alpine, and forest habitats. The resulting presettlement distribution of potential habitat for Greater Sage-Grouse encompassed 1 200 483 km(2), With the species' current range 668 412 km(2). The distribution of potential Gunnison Sage-Grouse habitat encompassed 46 521 km(2), with...
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We estimated survival rates of greater sage-grouse (Centrocercus urophasianus) in North Park, Colorado, USA, from band-recovery data of 6,021 birds banded during spring, 1973-1990, with recoveries through 1993. Average annual adult female survival ((S) over bar = 0.59, SE = 0.011) was greater than average adult male survival ((S) over bar = 0.37, SE = 0.007), and average subadult (<1 yr old at time of banding) female survival ((S) over bar = 0.77, SE = 0.030) was greater than average subadult male survival ((S) over bar = 0.63, SE = 0.034). Four weather covariates (spring and winter precipitation and temperature) did not contribute to predicting annual survival. Published in Journal of Wildlife Management, volume...
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The decline in abundance of the newly recognized Gunnison sage grouse (Centrocercus minimus) in southwestern Colorado is thought to be linked to loss and fragmentation of its habitat, sagebrush (Artemisia) vegetation. We documented changes in sagebrush-dominated areas between the 1950s and 1990s by comparing low level aerial photographs taken in these time periods. We documented a loss of 20% or 155,673 ha of sagebrush-dominated areas in southwestern Colorado between 1958 and 1993. The amount of sagebrush-dominated area was much higher and loss rates were much lower in the Gunnison Basin. We also found that 37% of plots sampled underwent substantial fragmentation of sagebrush vegetation. If current trends of habitat...
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