scholarly journals Winter bat activity in the Canadian prairies

2006 ◽  
Vol 84 (8) ◽  
pp. 1079-1086 ◽  
Author(s):  
C.L. Lausen ◽  
R.M.R. Barclay

Periodic arousal from hibernation among mammalian hibernators is poorly understood. In bats, arousal is often associated with flight. We acoustically monitored two rocky areas along the Red Deer River in southeastern Alberta for bat activity in autumn, winter, and spring months. We found bats to be active in all months and at unexpectedly cold temperatures (coldest activity –8 °C). Bats were active even when ambient temperatures remained below 0 °C during the day and night. We documented Myotis ciliolabrum (Merriam, 1886), Myotis evotis (H. Allen, 1864), and Eptesicus fuscus (Beauvois, 1796) flying outside hibernacula in winter. Active E. fuscus that we captured in mid-winter of 2004–2005 weighed less than bats captured in the fall, but masses ranged from 14.0 to 21.0 g, indicating that some individuals still had fat reserves. Captured individuals were of various ages, with a male bias. Using radiotelemetry, we located the first natural rock-crevice hibernacula for male and female E. fuscus in the Canadian prairies. Winter roosts were narrow, deep rock crevices or erosion holes located in steep valley walls. We found evidence to suggest that dehydration may be a driving force for winter flights.

2016 ◽  
Vol 94 (12) ◽  
pp. 829-836 ◽  
Author(s):  
B.J. Klüg-Baerwald ◽  
L.E. Gower ◽  
C.L. Lausen ◽  
R.M. Brigham

Winter activity of bats is common, yet poorly understood. Other studies suggest a relationship between winter activity and ambient temperature, particularly temperature at sunset. We recorded echolocation calls to determine correlates of hourly bat activity in Dinosaur Provincial Park, Alberta, Canada. We documented bat activity in temperatures as low as −10.4 °C. We observed big brown bats (Eptesicus fuscus (Palisot de Beauvois, 1796)) flying at colder temperatures than species of Myotis bats (genus Myotis Kaup, 1829). We show that temperature and wind are important predictors of winter activity by E. fuscus and Myotis, and that Myotis may also use changes in barometric pressure to cue activity. In the absence of foraging opportunity, we suggest these environmental factors relate to heat loss and thus the energetic cost of flight. To understand the energetic consequences of bat flight in cold temperatures, we estimated energy expenditure during winter flights of E. fuscus and little brown myotis (Myotis lucifugus (Le Conte, 1831)) using species-specific parameters. We estimated that winter flight uses considerable fat stores and that flight thermogenesis could mitigate energetic costs by 20% or more. We also show that temperature-dependent interspecific differences in winter activity likely stem from differences between species in heat loss and potential for activity–thermoregulatory heat substitution.


The Auk ◽  
2001 ◽  
Vol 118 (1) ◽  
pp. 116-136 ◽  
Author(s):  
Maria Elena Pereyra ◽  
Martin L. Morton

Abstract The Dusky Flycatcher (Empidonax oberholseri), a small, open-nesting Neotropical migrant, is a relatively common summer inhabitant of subalpine environments in the western and southwestern United States. Nestling growth and development of thermoregulation were studied in a population at Tioga Pass (3,000 m) in the eastern Sierra Nevada of California. Despite the selective advantages that might be expected from accelerating rates of growth and thermoregulatory development, in an environment where the season was relatively short and cold temperatures and inclement weather were common, there was little evidence of adaptive modification in either of those parameters; growth rates were comparable to those of other tyrant flycatchers. Feather eruption began around day 5, brushing in dorsal and ventral tracts began two days later, and brushing of the flight feathers around day 9. Asymptotic body masses were attained around day 12, but nestlings did not fledge for another 4 to 5 days. The physiological development of endothermy was closely correlated with increases in body mass and accompanying decreases in surface-area-to-volume ratio and age, but was not significantly correlated with changes in plumage development, when mass and age were statistically controlled. On exposure to ambient temperatures between −3 and 5°C for 10 min (roughly twice as long as the average female bout of inattentiveness), individual nestlings were unable to prevent deep hypothermia until after day 7. Homeothermy, at 80% of adult levels, was not attained until after day 12, although broods of nestlings maintained relatively stable body temperatures as early as day 5. Whereas clutch sizes in this population generally ranged from two to four eggs, the most stable thermal environments were provided by broods of three or four chicks. Although broods of nestlings were generally able to maintain temperatures within 5°C of adult levels, temperature profiles during storms indicated a remarkable capacity for nestlings to tolerate temperatures in the nest as low as 15°C for periods as long as 4 h without apparent ill effect.


Koedoe ◽  
1973 ◽  
Vol 16 (1) ◽  
Author(s):  
D.A. Els

Changes occuring in marrow fat reserves of animals have been used as an indicator of their physical condition (Cheatum, 1949; Riney, 1955). Cheatum correlated his visual estimate with a chemical analysis and Riney used four different condition classes on red deer  (Cervus elaphus) for both colour and texture.


1980 ◽  
Vol 58 (7) ◽  
pp. 1341-1346 ◽  
Author(s):  
Les W. Gyug ◽  
John S. Millar

Fat content (FAT), lean dry weight (LDW), and caloric content (KCAL) were examined in a natural subarctic population of Peromyscus maniculatus. FAT was not significantly correlated with size (LDW) of the animal. FAT of adult males was negatively correlated with minimum ambient temperatures and was not correlated with reproductive condition. LDW of adult males did not vary in relation to season. FAT of prebreeding adult females was high and decreased in response to breeding, but LDW increased in response to breeding so that KCAL remained constant. KCAL was low in adult females only after the breeding season. Mice dying in live traps had significantly lower FAT than did any other group of adults indicating that wild mice do not normally deplete their fat reserves. KCAL of postweaning young increased with age due to an increase in LDW but not in FAT. We suggest that fat levels are intrinsically controlled in wild Peromyscus according to the probability of having to make extraordinary energy expenditures and are not simply subject to extrinsic controls through the balance of food availability and energy demands.


PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258801
Author(s):  
Rosanna N. Punko ◽  
Robert W. Currie ◽  
Medhat E. Nasr ◽  
Shelley E. Hoover

The epidemiology of Nosema spp. in honey bees, Apis mellifera, may be affected by winter conditions as cold temperatures and differing wintering methods (indoor and outdoor) provide varying levels of temperature stress and defecation flight opportunities. Across the Canadian Prairies, including Alberta, the length and severity of winter vary among geographic locations. This study investigates the seasonal pattern of Nosema abundance in two Alberta locations using indoor and outdoor wintering methods and its impact on bee population, survival, and commercial viability. This study found that N. ceranae had a distinct seasonal pattern in Alberta, with high spore abundance in spring, declining to low levels in the summer and fall. The results showed that fall Nosema monitoring might not be the best indicator of treatment needs or future colony health outcomes. There was no clear pattern for differences in N. ceranae abundance by location or wintering method. However, wintering method affected survival with colonies wintered indoors having lower mortality and more rapid spring population build-up than outdoor-wintered colonies. The results suggest that the existing Nosema threshold should be reinvestigated with wintering method in mind to provide more favorable outcomes for beekeepers. Average Nosema abundance in the spring was a significant predictor of end-of-study winter colony mortality, highlighting the importance of spring Nosema monitoring and treatments.


Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2162
Author(s):  
Agrafena Efremova ◽  
Georgia Colleluori ◽  
Mikhail Thomsky ◽  
Jessica Perugini ◽  
Marina Protasoni ◽  
...  

Cold-exposure promotes energy expenditure by inducing brown adipose tissue (BAT) thermogenesis, which over time, is also sustained by browning, the appearance, or increase, of brown-like cells into white fat depots. Identification of circulating markers reflecting BAT activity and browning is crucial to study this phenomenon and its triggers, also holding possible implications for the therapy of obesity and metabolic diseases. Using RT-qPCR, we evaluated the peripheral blood mononuclear cells (PBMC) expression profile of regulators of BAT activity (CIDEA, PRDM16), white adipocytes browning (HOXC9 and SLC27A1), and fatty acid β-oxidation (CPT1A) in 150 Siberian healthy miners living at extremely cold temperatures compared to 29 healthy subjects living in thermoneutral conditions. Anthropometric parameters, glucose, and lipid profiles were also assessed. The cold-exposed group showed significantly lower weight, BMI, hip circumference, and PBMC expression of CIDEA, but higher expression of HOXC9 and higher circulating glucose compared to controls. Within the cold-exposed group, BMI, total cholesterol, and the atherogenic coefficient were lower in individuals exposed to low temperatures for a longer time. In conclusion, human PBMC expresses the brown adipocytes marker CIDEA and the browning marker HOXC9, which, varying according to cold-exposure, possibly reflect changes in BAT activation and white fat browning.


2017 ◽  
Vol 10 (4) ◽  
pp. 253-258 ◽  
Author(s):  
Motti Charter ◽  
Ido Izhaki ◽  
Kobi Meyrom ◽  
Shauli Aviel ◽  
Yossi Leshem ◽  
...  

Even though the Barn Owl ( Tyto alba) is distributed worldwide, little information is available on how weather affects Barn Owl breeding outside of Europe and North America. For instance, if cold temperatures can negatively influence population dynamics in temperate regions, heat could have a similar negative effect in arid regions. We have studied a breeding population of Barn Owls in a semi-arid agricultural environment over 13 years in Israel in order to determine whether lack of rain and hot ambient temperatures impair Barn Owl reproductive success. The percentage of nest boxes occupied by Barn Owls was not related to any of the weather variables, whereas the number of nestlings per Barn Owl pair and the percentage of pairs that succeeded to fledge young was lower in years when it started to rain later in the season and when the minimum daily temperature was higher during the breeding season. In comparison to temperate regions, heat is detrimental to Barn Owl breeding and early precipitation is probably important in boosting vegetation and, in turn, the abundance of small mammals, the Barn Owl's staple food.


1997 ◽  
Vol 45 (2) ◽  
pp. 145 ◽  
Author(s):  
D. J. Hosken

Nyctophilus major is the largest member of its Australian-centred genus. Flow-through respirometry was used to investigate the thermal and metabolic physiology of adult N. major from south-western Australia. Oxygen consumption, carbon dioxide production, respiratory quotient, evaporative water loss and thermal conductance were measured at ambient temperatures of 5–40C. N. major was thermally labile and could be euthermic or torpid at low Ta. N. major entered into and spontaneously aroused from torpor at Tas as low as 5C, and became torpid at Tas as high as 23C. Like other temperate-zone Australian vespertilionid bats, some torpid N. major maintained a relatively high Tb at low Ta. Body mass and the duration of captivity had no detectable effect on the thermal responses of bats. The basal metabolic rate (BMR) of N. major was 85% of predicted, and falls within the the range of mass-specific BMRs reported for vespertilionid bats. While mean torpid á VO2 was reasonably high, torpor still facilitates substantial metabolic savings. However, because of the high á VO2 , N. major may not be able to remain torpid for more than about 60 days, relying solely on fat reserves. The evaporative water loss (EWL) of euthermic and torpid N. major was also high, although EWL during torpor was reduced compared with euthermy. Wet conductance was lower than predicted and probably relates to the solitary, tree-roosting habits of N. major. As has been reported for other bats, conductance values during torpor were lower than those during euthermy, but when torpid bats maintained a large ( Tb – Ta) differential at low Ta or became torpid at relatively high Ta , conductance values approached euthermic levels.


1994 ◽  
Vol 191 (1) ◽  
pp. 59-88 ◽  
Author(s):  
J Olson

The ontogeny of shivering thermogenesis was investigated in the altricial red-winged blackbird (Agelaius phoeniceus). Two indices of heat production ­ the rate of oxygen consumption (V(dot)O2) of the bird and the electromyographic (EMG) activity of the pectoralis (PECT) and gastrocnemius (GAST) muscles ­ were measured simultaneously in adult and nestling red-winged blackbirds as they were subjected first to thermoneutral temperatures and subsequently to progressively colder ambient temperatures (Ta). The ontogenetic changes in both indices indicated that the capability for thermogenesis in nestling red-winged blackbirds improved markedly with age. The metabolic rates of 3-day-old nestlings decreased during exposure to gradually falling ambient temperatures; at best, these nestlings were only able to maintain mass-specific V(dot)O2 at levels similar to or slightly above the resting metabolic rate at thermoneutral temperatures (RMR) for a short time before metabolic rates decreased with further cooling. Shivering was detected only in the PECT muscles and was of a relatively low intensity (maximum of sevenfold increase in intensity over basal levels). The 5-day-old nestlings increased mass-specific V(dot)O2 modestly (approximately 1.4-fold) above RMR and attained slightly higher maximal factorial increases in the EMG activity of the PECT (maximum of 18-fold basal levels) when exposed to the same experimental conditions. Shivering was also detected in the GAST muscles of these birds. The most striking improvements in both measures observed during the nestling period occurred between day 5 and day 8. Eight-day-old nestlings increased metabolic rates by approximately 2- to 2.5-fold over basal levels and sustained these elevated rates for longer before becoming hypothermic. Both the PECT and GAST muscles contributed significantly to shivering thermogenesis, and these older nestlings attained much higher factorial increases in the intensity of shivering (up to 72-fold) during exposure to cold temperatures. In addition, both the range and magnitude of the dominant frequencies of muscle activity in the PECT increased during postnatal development. The PECT muscles were a principal site of shivering thermogenesis in all nestling and adult red-winged blackbirds studied here. Shivering in these muscles was a 'first line defense' against cold; the threshold temperature for shivering in the PECT muscles coincided with the lower critical temperature for oxygen consumption (TLC), and the subsequent increases in EMG activity in this muscle with further cooling correlated well with the corresponding increases in mass-specific V(dot)O2.


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