Contents Page List of tables 8 List of figures Acknowlegements 13 Executive summary 14 14 Food habits 15 Activity Cratering dynamics Late spring Characteristics of the range 15 Habitat selection 1° Food habits 16 Activity Late spring range use by bulls 17 Summer Movements and distribution 18 Insects and weather 18 Climate and weather patterns 18 Caribou response to insects 18 Activity, food and habitat • 18 Energetic implications CHAPTER 1. Introduction CHAPTER 2. Winter Terrain 28 Surficial geology Historical winter distribution Methods 34 Snow • Lichen biomass Fire history Results • Snow Lichen biomass Fire history Discussion Snow Lichen biomass Fire history Summary : Food habits Methods Results and discussion Effect of analysis at different times 48 Differences among years 48 Differences over winter 49 Seasonal diets 49 Fecal sample versus ingested diet 49 Conclusions 51 Winter activity 51 Methods 51 Results Band size 53 Activity pattern Activity budgets Proportional use of active periods 57 Discussion 57 Effect of daylength on percent lying 57 Activity budgets 59 Range quality 60 Cratering dynamics 61 Methods 61 Results and discussion Conclusions Conclusions from winter 70 CHAPTER 3. Late spring Calving grounds Porcupine caribou calving distribution Characteristics of the range 78 Methods 78 4 Rangifer, Special Issue No. 8, 1993 Weather Biomass Tussock density 79 Phenology Nutrients Results and discussion Weather • • • • 79 Phenology • Biomass 81 Tussock density 82 Nutrients Summary Habitat selection Methods Results and discussion • Food habits Methods 91 Results 91 Effect of analysis at different times 91 Differences between periods 91 Differences among years Fecal sample versus ingested diet 92 Discussion Caribou activity Methods Results Band Size Movement rate 95 Active and bedded cycles 95 Activity budgets Focal animal observations 97 Nursing Discussion Summary discussion 101 Spring range of bulls 103 107 Habitat selection •. RangiSer, Special Issue No. 8 1993 5 Food habits Summary and conclusions 109 Comparison of bulk and cows 110 CHAPTER 4. Summer Introduction 113 Study area. : 113 Summer movements 114 Historical Herd movements-1984, 1985 Methods Results Discussion Activity of dipterans in relation to date and weather 120 121 Oestrid flies 121 Result Mosquito sweeps 122 Discussion Influence of season and weather on Dipterans 123 Climate and weather patterns 126 Introduction Methods Results and discussion Data summaries Average daytime air temperatures 127 Average hourly air temperatures 127 Average hourly wind speeds 128 Correlations between permanent and temporary sites 12 Regional weather versus insects 129 Response of groups and individual caribou to insect harassment 131 133 Annoyance responses of individual caribou 133 Caribou annoyance responses in relation to date and weather 13 Relationship between position in group and insect harassment 13 Discussion Caribou group dynamics 134 Behavioral responses of individual caribou 135 Position in a group 135 Activity budgets, food and habitat selection 13...

The focus of this article is on the temporal capacity of short-term visuomotor memory as reflected by changes in the time and frequency patterns of force output. In experiment 1, subjects produced continuous force output (isometric index finger flexion) to a target force level (from 5 to 75% of maximum voluntary contraction, MVC) displayed on a video monitor for 20 s. In the full visual feedback condition, visual feedback was displayed throughout each trial, while, for the visual feedback-withdrawal condition, visual feedback was occluded for the final 12 s of each trial. With visual feedback present, subjects matched their force output to the target force level for 20 s. When visual feedback was removed, participants continued to match the target force level for approximately 0.5-1.5 s; thereafter force output decayed exponentially. In line with this decay, short time-frequency analysis revealed a decrease in force intensity in the 0- to 5-Hz band. Force level did not influence the time before decay; however, greater forces led to larger decay. Experiment 2 assessed whether the force decay in experiment 1 was a property of visual or motor short-term memory by having participants set their own target force levels with no visual information provided throughout. In agreement with the findings of experiment 1, force output decayed, emphasizing the importance of a motor memory source. It is concluded that the 0.5- to 1.5-s time period represents a limit on the temporal capacity that precise visuomotor information is held in short-term memory.

We determined seasonal changes in body mass and composition of arctic caribou (Rangifer tarandus granti) in relation to age and reproductive status. Chemical composition was determined for 37 caribou calves from the Central Arctic Herd ranging from 1 to 134 days of age and for 15 adult females collected from the same herd in October, May, and July. Body composition of 5 fetuses from the Central Arctic Herd, 13 calves from the Porcupine Herd, and 10 captive male reindeer (R. t. tarandus) was determined for comparison. Between October 1989 and May 1990, body fat and protein of adult females declined by maxima of 45 and 29%, respectively; an additional 32% of fat was lost between May and July. Mobilization of large amounts of fat and protein suggests winter undernutrition. Chemical composition and growth patterns of calves did not differ between the herds. The growth rate of Central Arctic Herd calves was high during the first 28 d post partum (402 gld), but both growth rate and fatness declined between 4 and 6 weeks of age (to 306 and -18.3 gld, respectively), perhaps in response to insect harassment. Birth masses of males and females did not differ, but by autumn, male calves were 9.1 kg heavier than females. Chemical components (water, fat, protein, ash) were highly correlated with body mass, ingesta-free body mass, and carcass mass. Percentages of fat and water were inversely related, but the intercept decreased with age. Marked seasonal hypertrophy of liver and kidneys was noted in caribou, suggesting the presence of mobilizable protein reserves. Seasonal changes in organ masses may also reflect variations in metabolic activity and nutrient intake.

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