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Research about Superior National Forest

Source-linked reports with geographic coverage including Superior National Forest.

25 records · Page 2Linked to original sources
USGS1990

Field testing of commercially manufactured capture collars on white-tailed deer

We conducted 31 tests of commercially manufactured capture collars on female white-tailed deer ( Odocoileus virginianus ) in the Superior National Forest, Minnesota, under temperatures from -37C to 22C. Deer were recaptured in 28 of the 31 tests; in the 3 failures, we remotely released the collars from the deer. Communication with the collars was achieved from up to 3.0 km on the ground and 26.5 km from the air.

Minnesota↗
USGS1990

Minimizing capture-related stress on white-tailed deer with a capture collar

We compared the effect of 3 capture methods for white-tailed deer ( Odocoileus virginianus ) on blood indicators of acute excitement and stress from 1 February to 20 April 1989. Eleven adult females were captured by Clover trap or cannon net between 1 February and 9 April 1989 in northeastern Minnesota. These deer were fitted with radio-controlled capture collars, and 9 deer were recaptured 7-33 days later. Trapping method affected serum cortisol (P < 0.0001), hemoglobin (Hb) (P < 0.06), and packed cell volume (PCV) (P < 0.07). Cortisol concentrations were lower (P < 0.0001) in capture-collared deer (0.54 ± 0.07 [SE] μg/dL) compared to Clover-trapped (4.37 ± 0.69 μg/dL) and cannon-netted (3.88 ± 0.82 μg/dL) deer. Capture-collared deer were minimally stressed compared to deer captured by traditional methods. Use of the capture collar should permit more accurate interpretation of blood profiles of deer for assessement of condition and general health.

Minnesota↗
USGS1989

Physiological assessment of deer populations by analysis of urine in snow

We compared the nutritional status of free-ranging white-tailed deer ( Odocoileus virginianus ) in 3 natural yards and 1 yard where deer were supplementally fed from 1 January to 31 March 1985 in northeastern Minnesota. We monitored deer nutritonal status by sequential collection and chemical analysis of urine in snow (snow-urine) for urea nitrogen (U), sodium (Na), potassium (K), calcium (Ca), and phosphorus (P). Dilution of urine by snow was corrected by comparing these data as ratios to creatinine (C). All deer remained in an early phase of undernutrition; however, declining trends of U:C, Na:C, and K:C in 2 natural yards indicated increasingly inadequate nutrition as winter progressed. Unaltered values of these ratios and P.C in snow-urine collected from the third natural yard reflected stable levels of nutrient availability. Significant (P < 0.05) elevations of Na:C, K:C, and P:C in 2 natural yards with similar snow regimes suggested initiation of nutritional recovery in deer during late March. In contrast, deep snow in the third natural yard restricted feeding activity and was associated with ratios that remained diminished. Elevated U:C, Na:C, and K:C provided physiological evidence of the higher nutritional status of supplementally fed deer throughout winter and their ability to increase nutrient intake during late March despite prolonged deep snow cover. Frequent and quantitative assessments of the physiological status of deer by snow-urine analysis provided an improved understanding of the relationship between snow cover and the nutritional well-being of these deer.

Minnesota↗
USGS1986

Mortality of white-tailed deer in northeastern Minnesota

Two hundred nine white-tailed deer ( Odocoileus virginianus ) were radiotracked in the central Superior National Forest, Minnesota, from 1973 through winter 1983-84; 85 deaths were recorded. Annual survival was 0.31 for fawns (< 1.0 years old), 0.80 for yearling (1.0-2.0 years old) females, 0.41 for yearling males, 0.79 for adult ( ≥ 2.0 years old) females, and 0.47 for adult males. Monthly survival rates were high from May through December (0.94-1.00), except for yearling (0.60) and adult (0.69) bucks during the November hunting season. Most mortality occurred from January through April when gray wolf (Canis lupus) predation was an important mortality source for all cohorts. Yearling males were most vulnerable to hunting and adult males to wolf predation.

Minnesota↗
USGS1982

An analysis of howling response parameters useful for wolf pack censusing

Gray wolves ( Canis lupus ) were studied from April-1972 through April 1974 in the Superior National Forest in northeastern Minnesota by radio-tracking and simulated howling. Based on replies during 217 of 456 howling sessions, the following recommendations were derived for using simulated howling as a census technique: (1) the best times of day are dusk and night; (2) July, August, and September are the best months; (3) precipitation and winds greater than 12 km/hour should be avoided; (4) a sequence of 5 single howls should be used, alternating 'flat' and 'breaking' howls; (5) trials should be repeated 3 times at about 2-minute intervals with the first trial at lower volume; and (6) the trial series should be repeated on 3 nights as close to each other as possible. Two censuses are described: a saturation census and a sampling census.

Minnesota↗
USGS1977

Productivity, mortality, and population trends of wolves in northeastern Minnesota

Population parameters, mortality causes, and mechanisms of a population decline were studied in wolves ( Canis lupus lycaon ) from 1968 to 1976 in the Superior National Forest. The main method was aerial radio-tracking of 129 wolves and their packmates. Due to a decline in white-tailed deer ( Odocoileus virginianus ), the wolf population decreased during most of the study. Average annual productivity varied from 1.5 to 3.3 pups per litter, and annual mortality rates from 7 to 65 percent. Malnutrition and intraspecific strife accounted equally for 58 percent of the mortality; human causes accounted for the remainder. As wolf numbers began to decline, pup starvation became apparent, followed by lower pup production, and then by increased intraspecific strife. At higher densities, adult pack wolves were the most secure members of the population, but as the population declined, they became the least secure because of intraspecific strife.

Minnesota↗