Per Ahlqvist

Risk of capture-related mortality in large free-ranging mammals: experiences from Scandinavia

Abstract Chemical capture and anaesthesia of free-ranging mammals will always involve some risk of mortality even in healthy animals. Deaths may be directly or indirectly attributable to the anaesthetic event itself (e.g. drug overdose, drowning during induction and dart trauma) or may be caused by secondary effects from the capture (e.g. stress, myopathy, trauma or instrumentation with radio-transmitters). In long-term research projects on five major wildlife species in Scandinavia, the capture-related mortality rates (number of captures) were: moose Alces alces 0.7% (N = 2,816), brown bears Ursus arctos 0.9% (N = 1,079), wolverines Gulo gulo 2.8% (N = 461), Eurasian lynx Lynx lynx 3.9% (N = 380), and gray wolves Canis lupus 3.4% (N = 89). We suggest that wildlife professionals should strive for a zero mortality rate but adopt the standard that a mortality rate of > 2% probably should not be accepted in any large mammalian species. This can be achieved by: 1) using an experienced professional capture team, 2) developing and following a capture protocol specific to each species, and 3) requiring that a mortality assessment be undertaken after any capture-related death. This assessment should re-evaluate the capture protocol, including how changes in anaesthetics and methodological approaches could have prevented the mortality.

Biomedical Protocols for Free-ranging Brown Bears, Gray Wolves, Wolverines and Lynx Editors

PREFACE Compilation of this document was initiated by the Norwegian Directorate for Nature Management in order to establish recommended protocols for capture, chemical immobilization, anesthesia and radiotagging of free-ranging brown bears (Ursus arctos), gray wolves (Canis lupus), wolverines (Gulo gulo) and Eurasian lynx (Lynx lynx). In addition, procedures to ensure proper sampling of biological materials for management, research and banking purposes have been included. The current protocols are based on nearly 3,000 captures of free-ranging brown bears, wolves, wolverines and lynx carried out from 1984 through 2012 in Scandinavia. Some of the results have been published as peer reviewed papers, conference presentations, theses, and reports. However, a large amount of data are still on file and will be published in the future. In addition, comprehensive reviews of the global literature on brown bears, wolves, wolverines and lynx have been carried out in order to include pertinent information from other sources. These protocols have been approved by all ongoing research projects on brown bears, wolves, wolverines and lynx in Scandinavia. We thank the contributors for their cooperative efforts. We also thank the Norwegian Directorate for Nature Management for their support.

Estimating total lynx Lynx lynx population size from censuses of family groups

Counts of reproductive units, i.e. family groups, constitute the main monitoring index for lynx Lynx lynx populations in Scandinavia. However, for some purposes it is necessary to extrapolate from the number of family groups to obtain an estimate of total population size. Using data on survival and reproduction from radio-marked lynx from three Scandinavian study areas, we simulated the lynx population structure in February. The average proportions of family groups out of all independent individuals, i.e. adults and yearlings, in these simulations were 21% ± 2.1 (SD), 22% ± 3.6 and 27% ±3.1 for the data sets from northern Sweden (Sarek), southeastern Norway (Hedmark) and south-central Sweden (Bergslagen), respectively, and the overall mean for all three study areas was 23% ± 3.8. This translated into extrapolation factors of 6.14 ± 0.44,6.24 ± 0.73 and 5.48 ± 0.40 for the three study areas, respectively, leading to an overall mean for all three study areas of 5.95 ± 0.64. We conclude, that it is possible to extrapolate from the number of family groups to obtain an estimate of total lynx population size with a statistical measure of uncertainty.

Biomass Flow and Scavengers Use of Carcasses after Re- Colonization of an Apex Predator

Background Reestablishment of apex predators influences the availability and distribution of biomass for scavengers and can therefore be an important agent for structuring species communities. We studied how the re-colonization of the Scandinavian Peninsula by wolves (Canis lupus) affected the amount and temporal variation in use of moose (Alces alces) carcasses. Methodology/Principal Findings We compared the availability of biomass from remains at wolf kills with those killed by hunters, vehicle collisions and natural death. Movement-triggered cameras monitored patterns of use on wolf kills and remains from hunter harvest by scavengers (n = 15 276) in relation to time of year, available carcass biomass, time since the death of the moose and presence of wolves. Remains from hunter harvest were the largest food source for scavengers both within wolf territories (57%) and in areas without wolves (81%). The total annual biomass available were similar in areas with (25 648 kg) and without (24 289 kg) wolves. Presence of wolves lowered the peak biomass available from hunter harvest in October (20%) and increased biomass available during December to August (38–324% per month). The probability of scavengers being present decreased faster with time at remains from hunter harvest compared to wolf kills and both the probability of being present and the number of visits by scavengers to wolf kills increased as the amount of biomass available on the carcass increased. Conclusions/Significance Wolves reduced the seasonal variation of biomass from moose carcasses and most important increased it during spring. Scavengers also visited wolf kills most frequently during spring when most scavenging species have young, which may lead to an increase in survival and/or reproductive success of scavengers within wolf territories. This applies both for abundant scavenging species that were the most frequent visitors at wolf kills and threatened scavengers with lower visit frequency.

Chemical Immobilization of Free-ranging Fallow Deer (Dama dama): Effect of Needle Length on Induction Time

Abstract We evaluated impact of the needle length, sex, and body condition on chemical immobilization induction time in 50 (29 males and 21 females) free-ranging fallow deer (Dama dama) in Sweden, 2006–11. Induction time is probably the single most important factor when immobilizing free-ranging wildlife with the use of a remote drug-delivery system. Induction times should be short to minimize stress and risk of injury, and to ensure that immobilized animals can be found and clinically monitored as soon as possible. We measured the distance between the darting location and where we recovered the immobilized animal and also the time occurring between the two events. We used two types of needles: 2.0 × 30– or 2.0 × 40–mm barbed needles with side ports. The most important result is that a 10-mm-longer dart needle can reduce the retrieval time substantially (>20 min) until an animal is under monitoring. On average after the darting, the retrieval time decreased from 51 to 29 min and the distance decreased from 519 m from the darting location to 294 m. We suggest that a needle length of 40 mm is preferable for immobilization of wild fallow deer, especially for animals in over-average–to–fat body condition.

Evaluation of Medetomidine-Ketamine and Atipamezole for Reversible Anesthesia of Free-ranging Gray Wolves (Canis lupus)

Twenty-eight anesthetic events were carried out on 24 free-ranging Scandinavian gray wolves (Canis lupus) by darting from a helicopter with 5 mg medetomidine and 250 mg ketamine during winter in 2002 and 2003. Mean±SD doses were 0.162±0.008 mg medetomidine/kg and 8.1±0.4 mg ketamine/kg in juveniles (7–10 mo old) and 0.11060.014 mg medetomidine/kg and 5.7±0.5 mg ketamine/kg in adults (>19 mo old). Mean±SD induction time was shorter (P<0.01) in juveniles (2.3±0.8 min) than in adults (4.1±0.6 min). In 26 cases, the animals were completely immobilized after one dart. Muscle relaxation was good, palpebral reflexes were present, and there were no reactions to handling or minor painful stimuli. Mild to severe hyperthermia was detected in 14/ 28 anesthetic events. Atipamezole (5 mg per mg medetomidine) was injected intramuscularly for reversal 98±28 and 94±40 min after darting in juveniles and adults, respectively. Mean±SD time from administration of atipamezole to coordinated walking was 38±20 min in juveniles and 41±21 min in adults. Recovery was uneventful in 25 anesthetic events, although vomiting was observed in five animals. One adult that did not respond to atipamezole was given intravenous fluids and was fully recovered 8 hr after darting. Two animals died 7–9 hr after capture, despite intensive care. Both mortalities were attributed to shock and circulatory collapse following stress-induced hyperthermia. Although effective, this combination cannot be recommended for darting free-ranging wolves from helicopter at the doses presented here because of the severe hyperthermia seen in several wolves, two deaths, and prolonged recovery in one individual.