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R. L. Linder

Publications and source records attributed to R. L. Linder.

4 recordsLinked to original sources
USGS1979

Prairie dog distribution in areas inhabited by black-footed ferrets

The distribution of black-tailed prairie dog ( Cynomys ludovicianus ) towns was delineated in a 1490 km 2 study area in Mellette County, South Dakota, and was examined to determine the characteristics of black-looted ferret ( Mustela nigripes ) habitat. Between 1964 and 1974, black-looted ferrets were observed on 14 prairie dog towns in this area. Eighty-six prairie dog towns, located throughout the study area, were not randomly distributed; towns were paired or clumped in spatial distribution. Mean distance between a town and its nearest neighbor was 2.4 km; mean distance between a ferret-occupied town and the nearest town was similar, 2.7 km. Management recommendations are to maintain at least eight towns per township, each at least 12 ha in size. Of these eight towns, two or more should exceed 40 ha.

South Dakota↗
USGS1969

A comparison of methods used to obtain age ratios of snow and Canada geese

The validity of group counts, cannon-net catches, and hunter-bag checks for estimating productivity of lesser snow geese ( Anser caerulescens caerulescens ) and small Canada geese ( Branta canadensis hutchinsii-parvipes complex) was studied at Sand Lake National Wildlife Refuge during the falls of 1965 and 1966. Age ratios of snow geese obtained from net-trapped samples were significantly higher (P < 0.01) than from group counts at the same site. Immature snow geese were shot in a significantly greater (P < 0.01) proportion than they existed in the population as determined by group counts. Cannon-net catches and hunter-bag checks of snow and Canada geese yielded age ratios which were biased because of behavioral characteristics of the geese. Immatures of both species were less wary of trap equipment and immature snow geese were more vulnerable to the gun than adults. It was believed that age ratios from group counts of snow geese were more representative of the population than those from net catches and hunter-bag checks. Sex ratios of net-trapped geese showed a preponderance of males for adult Canada and adult and immature snow geese, whereas females were predominant in the immature segment of Canada geese. Hunter selectivity of blue- or white-phase snow geese was not observed at Sand Lake Refuge. Differential vulnerability to hunting between snow and Canada geese resulted from differences m feeding-flight behavior.

South Dakota↗