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Understanding how bats manage their energy budgets under different thermal conditions is an important component in understanding the limits of distribution and their ability to cope with environmental changes, such as ongoing climate change. In particular, as multiple species of bats are predicted to increase their distribution northward, this thesis aimed to estimate energy consumption (i.e., metabolic rate) in bats currently inhabiting high latitudes in the northern hemisphere. Metabolic rate was estimated using indirect calorimetry, while bats were exposed to an increasing temperature profile during daytime. This was supplemented with reviewing previously published papers for comparison. Interestingly, energy consumption in bats at high northern latitudes is affected by a multitude of factors. For instance, the extent to which torpor is used can be highly dependent on energy availability, as bats with higher body mass delay torpor entry, and perform more costly arousals at lower ambient temperatures to achieve normothermic body temperatures. Despite being exposed to near-freezing temperatures, increased metabolic rate, indicating a propensity to prevent body temperature from passing past a critical level, was only evident within half the bats in brown long-eared bat (Plecotus auritus), and none in northern bat (Eptesicus nilssonii). Length of time needed to enter torpor, can also differ between species, primarily as a result of differences in whole-animal metabolic rate, and thermal effects on cooling. To date, basal metabolic rate has only been estimated in 3.4% of all species of the Vespertilionidae family. This limited dataset contains too few data points to perform analysis on how basal metabolic rate differs between sexes, season, and reproductive state at a grander scale. Accordingly, body mass is the main predictor describing variation in basal metabolic rate between species. Similarly, on a global scale, the minimum torpor metabolic rate is fairly universal across different habitats and species. Minimum torpor metabolic rates are first and foremost affected by ambient temperature. However, some species of bats inhabiting more arid climate zones present minimum torpor metabolic rates at higher ambient temperatures, thus indicating a need to defend a higher body temperature. In its totality, this thesis provides further insight into the physiological flexibility of bats living at high latitudes in the northern hemisphere. With an opportunistic use of torpor to manage their energy budgets, and a particularly wide thermoneutral zone, bats can sustain long periods of limited food supply. On a global scale, energy consumption in bats has been largely overlooked, as work so far has been limited to a few species, often focused around small geographic areas. Thus, to better predict, manage, and conserve species in the face of climate change, more work is needed to understand the physiological and behavioral responses of bats to different environmental conditions in bats. Fulltext not available more...

The home range use and habitat selection of four providing male Tengmalm's owls (Aegolius funereus) were studied by using radio telemetry, and simultaneously recording prey deliveries by a video camera positioned inside the nest box of each nest. The camera allowed prey identi cation and made it possible to assign prey deliveries to locations in the eld, i.e, the last observation x before a delivery. 100% MCP home ranges averaged 219.4 ha, whereas 95% kernel home ranges had a mean size of 310 ha, and decreased with increasing proportion of high productivity areas in the home range. Owls did not shift hunting areas from one night to the next, but rather changed it gradually over time. Habitat selection was estimated by calculating the distance from each observation x (N=458) and from each random plot (N=480) to the nearest patch of each habitat class, and testing for di erences using logistic regression. The owls showed a particularly strong selection for hunting in forest age class I (clear-cuts and plantations), which is the primary habitat of their main prey, Microtus voles. They hunted closer to areas of medium and high productivity, and farther from areas of low productivity and impediment than expected by random. This may be related to abundance and availability of prey animals which select areas of dense vegetative cover. Bogs did not seem to be selected, but due to the low proportion in two of the nests, the results were inconclusive. Male owls both hunted and captured prey closer to the nest than expected by random. Additionally, prey captures were located closer to high productivity and farther from areas of impediment than expected by random. Shrews were captured closer to areas of high productivity than expected by random, which is in accordance with other ndings that suggest that the density of shrews increases with productivity. Shrews seemed to be excluded from certain habitats by Microtus voles because captures of shrews were located farther from forest age class I than captures of Microtus voles. Although the pro tability of transporting prey items back to the nest in theory is related to prey size and distance from the nest, the larger Microtus voles were not transported to the nest from longer distances than the smaller shrews. An owl returned to the area where it captured the last prey more often than expected by random. Thus, the owls utilized a win-stay strategy. The present study is the rst to combine radio tracking and video monitoring to determine habitat speci c prey capture in Tengmalm's owl and highlight the importance of habitat productivity for hunting owls. Sammendrag Hjemmeomr adet og habitat seleksjonen til re Perleugle (Aegolius funereus) hanner ble studert ved bruk av radio telemetri, samtidig som byttedyrleveringer ble registrert av et videokamera plassert inni reir-kassen til hvert reir. Kameraopptakene tillot identi kasjon av byttedyr og gjorde det mulig a koble byttedyrleveringer til lokasjoner i felt, i hovedsak siste observasjon f r levering. 100% MCP hjemmeomr a der hadde en gjennomsnittlig st rrelse p~219.4 ha, mens 95% kernel hjemmeomr ader hadde en gjennomsnittlig st rrelse p~310 ha, og minket med kende andel av omr ader med h y produktivitet i hjemmeomr adet. Perleuglene byttet ikke jaktomr a de for hver natt, men skiftet jaktomr a de gradvis over tid. Habitatseleksjon ble estimert ved akalkulere avstanden fra hver observasjon (N=458) og fra hvert random plot (N=480) til n rmeste omr ade av hver habitatkategori, for deretter ateste om det var signi kante forskjeller mellom disse ved bruk av logistisk regresjon. Perleuglene viste en spesielt stor seleksjon for skog i aldersklasse I (hogst ater og plantasjer), som er prim rhabitatet for Perleugles hovedbyttedyr, Microtus. I tillegg jaktet de n rmere omr ader med medium og h y produktivitet, og lenger fra omr ader av lav produktivitet og impediment enn forventet av tilfeldig valg. Dette henger muligens sammen med tallrikhet og tilgjengelighet av byttedyr som foretrekker tett vegetasjonsdekke. Myromr ader s a ikke ut til a bli selektert, men grunnet lav tilgjengelighet i to av reirene var resultatene tvetydige. Hannene jaktet og fanget byttedyr n rmere reiret enn forventet ved tilfeldig valg. I tillegg var fangster av byttedyr lokalisert n rmere omr ader med h y produktivitet og lengre fra omr ader med impediment enn forventet ved tilfeldig valg. Spissmus ble fanget n rmere omr ader med h y produktivitet enn forventet ved tilfeldig valg. Dette stemmer overens med andre funn som indikerer at tettheten av spissmus ker med kende produktivitet. Spissmus s a ut til a bli ekskludert fra enkelt habitat av Microtus fordi fangstpunkter av spissmus var lokalisert lengre fra aldersklasse I enn fangstpunkter av Microtus. Selvom l nnsomheten ved a transportere byttedyr tilbake til reiret er relatert til byttedyrst rrelse og avstand fra reiret, ble ikke Microtus transportert lengre enn spissmus til tross for forskjeller i st rrelsen. Uglene returnerte oftere til forrige fangstomrde oftere enn forventet ved tilfeldig valg. Med andre ord utnyttet Perleuglene en "vinn-bli" strategy. Dette studiet er det frste til a kombinere radio peiling og video overv akning til a fastsl a habitat-spesi kk byttedyr fangst hos Perleugle og belyser viktigheten av habitat produktivitet for jaktende ugler. more...

Glukokortikoider (GK) er ofte brukt som et mål på stress hos dyr. Om dyret er stresset over en lengre periode kan det få skadelige konsekvenser. GK konsentrasjonen er ofte målt i blodet, men i senere år har målinger fra fekale glukokortikoider metabolitter (FGM) fra avføringsprøver blitt mere brukt. I flaggermus artene Plecotus auritus og Myotis mystacinus ble det målt i denne studien om håndtering av fekalt kortisol (FK), og hvordan det varierer over tid. Dette var også gjort for å validere om den brukte analysen kunne oppdage de ulike forandringene i FK i de to artene. Flaggermusene var holdt i bomullsposer og plastikk bokser og sjekket hvert 30 minutt i 3 timer og hver time til 06:00. Prøvene var oppbevart i en fryser til de ble analysert av et Kortisol ELISA sett. FK var høyst variabel i tiden etter fangst. I tids intervallet 0-3 timer etter fangst toppet den individuelle gjennomsnitts sentrerte FK seg etter 1.6t før det gikk ned. Mellom tidsintervallet 3-7 timer etter fangst økte også den individuelle gjennomsnittlig sentrete FK, men det var høy varians mellom individer. Dette viser at håndtering fører til en økning i FK i P. auritus og M. mystacinus, og den brukte analysen vil oppdage disse endringene. Transport kan være grunnen til økning mellom 3-7 timer for P. auritus, men det er forskjellige individuelle forskjeller som kan være årsaken til både økningen og variansen. Både FKM og blod prøver burde bli vurdert når man undersøker GK, men hvilke man skal bruke er avhengig av studiet. Glucocorticoids (GC) are often used as a measurement of stress in animals. If an animal is stressed over a longer period of time, deleterious effects may develop. GC concentrations are often measured in blood, but recently measurements of faecal glucocorticoid metabolites (FGM) from faecal samples are more often used. In the bat species Plecotus auritus and Myotis mystacinus I measured if handling leads to an increase in faecal cortisol (FC), and how it varies over time. The assay used was also validated to investigate if it detected the expected changes in FC measurements in these two species. The bats were captured using mists net and held in cotton bags and plastic containers, they were checked every 30 minutes for 3 hours and every hour until 06:00h. The samples were stored in a freezer until analysed by the Cortisol ELISA kit. The FC was highly variable following capture. However, in the time interval 0-3 hours after capture the individual mean centred peaked after 1.6h before declining. Between 3-7 hours after capture the individual mean centred FC also increased, however with a higher variance between the individual bats. This shows that handling leads to an increase in FC in P. auritus and M. mystacinus, and that the assay used detected these changes. Transportation may be the cause for the increase between 3-7 hours for P. auritus, however there are many individual factors that may have been the cause for the increase and the variance between the individuals. Both FGM and blood sampling should be considered when investigating GC, however which one to use will depend on the study. more...