Ideal conditions for increased trapping success of pygmy rabbits (Brachylagus idahoensis) across the Great Basin

Sagebrush-steppe ecosystems are one of the most imperiled ecosystems in North America and many of the species that rely on these habitats are of great conservation concern. Pygmy rabbits (Brachylagus idahoensis) are one of these species. They rely on sagebrush year-round for food and cover, and are understudied across their range in the intermountain west due in part to their recalcitrance to standard capture techniques. Identifying an efficient and minimally biased trapping method therefore is a critical first step in learning more about this species. We assessed how trap orientation and weather characteristics influenced trap success for Tomahawk traps placed in and around pygmy rabbit burrows by carrying out trapping surveys at 16 occupied pygmy rabbit sites across the Great Basin from 2016 to 2018. We found that pygmy rabbits had a greater probability of being captured in traps with the open end facing away from burrow entrances. Pygmy rabbits also were more likely to be captured on clear days (0–5% cloud cover) and during periods of cooler temperatures during summer months (June–August). We found no evidence that sex or age ratios differed, or that individuals differed meaningfully, in their preference for certain trap orientations. To increase trap success for pygmy rabbits, we suggest maximizing trapping effort during summer months, at dawn, and maximizing the proportion of Tomahawk traps facing away from burrow entrances. We anticipate that our monitoring protocol will enable more effective research into the ecology and conservation of this cryptic and potentially imperiled species.

Characteristics of the Growth and Development of pygmy rabbits using the preparation «EM-Kurunga»

Анализируется воздействие микробиологического препарата «ЭМ-Курунга» на рост и развитие карликовых кроликов первых трёх месяцев жизни. Исследуется влияние данного препарата на живую массу крольчат, гнезда, прирост живой массы, а также на индекс сбитости и показатели крови крольчат. В качестве объекта исследования выступили крольчата пород карликовый баран и карликовый заяц. Проведённые исследования показали, что подопытные животные отличались незначительным преимуществом при оценке прироста живой массы. При оценке живой массы гнезда прослеживается тенденция к незначительному увеличению под воздействием биологически активной добавки «ЭМ-Курунга». Индекс сбитости под воздействием препарата не изменился. Количество эритроцитов и гемоглобина у подопытных животных было выше, чем в контрольных группах. Все полученные данные свидетельствуют, что воздействие препарата на исследованные показатели незначительно и недостоверно. The effect of the microbiological preparation "EM-Kurunga" on the growth and development of pygmy rabbits of the first three months of life is analyzed. The effect of this preparation on the live weight of infant rabbits, nests, body weight gain as well as on the blockiness index and blood values of infant rabbits is studied. The object of the study was infant rabbit of the pygmy ram and pygmy hare breeds. Conducted researches have shown that experimental animals had a slight advantage in assessing the body weight gain. When assessing the live weight of the nest, there is a tendency to slightly increase under the influence of the biologically active supplement "EM-Kurunga". The blockiness index under the influence of the preparation did not change. The numbers of red blood cells and hemoglobin in the experimental animals were higher than in the control groups. All the obtained data indicate that the effect of the preparation on the examined indicators is insignificant and unreliable.

Seasonal temperature acclimatization in a semi-fossorial mammal and the role of burrows as thermal refuges

Small mammals in habitats with strong seasonal variation in the thermal environment often exhibit physiological and behavioral adaptations for coping with thermal extremes and reducing thermoregulatory costs. Burrows are especially important for providing thermal refuge when above-ground temperatures require high regulatory costs (e.g., water or energy) or exceed the physiological tolerances of an organism. Our objective was to explore the role of burrows as thermal refuges for a small endotherm, the pygmy rabbit (Brachylagus idahoensis), during the summer and winter by quantifying energetic costs associated with resting above and below ground. We used indirect calorimetry to determine the relationship between energy expenditure and ambient temperature over a range of temperatures that pygmy rabbits experience in their natural habitat. We also measured the temperature of above- and below-ground rest sites used by pygmy rabbits in eastern Idaho, USA, during summer and winter and estimated the seasonal thermoregulatory costs of resting in the two microsites. Although pygmy rabbits demonstrated seasonal physiological acclimatization, the burrow was an important thermal refuge, especially in winter. Thermoregulatory costs were lower inside the burrow than in above-ground rest sites for more than 50% of the winter season. In contrast, thermal heterogeneity provided by above-ground rest sites during summer reduced the role of burrows as a thermal refuge during all but the hottest periods of the afternoon. Our findings contribute to an understanding of the ecology of small mammals in seasonal environments and demonstrate the importance of burrows as thermal refuge for pygmy rabbits.