Identifying individual polar bears at safe distances:A test with captive animals

The need to recognise individuals in population and behavioural studies has stimulated the development of various identification methods. A commonly used method is to employ natural markers to distinguish individuals. In particular, the automated processing of photographs of study animals has gained interest due to the speed of processing and the ability to handle a high volume of records. However, automated processing requires high-quality photographs, which means that they need to be taken from a specific angle or at close distances. Polar bears Ursus maritimus, for example, may be identified by automated analysis of whisker spot patterns. However, to obtain photographs of adequate quality, the animals need to be closer than is usually possible without risk to animal or observer. In this study we tested the accuracy of an alternative method to identify polar bears at further distances. This method is based on distinguishing a set of physiognomic characteristics, which can be recognised from photographs taken in the field at distances of up to 400 m. During five trials, sets of photographs of 15 polar bears from six zoos, with each individual bear portrayed on different dates, were presented for identification to ten test observers. Among observers the repeatability of the assessments was 0.68 (SE 0.011). Observers with previous training in photogrammetric techniques performed better than observers without training. Experience with observing polar bears in the wild did not improve skills to identify individuals on photographs. Among the observers with photogrammetric experience, the rate of erroneous assessment was on average 0.13 (SE 0.020). For the inexperienced group this was 0.72 (SE 0.018). Error rates obtained with automated whisker spot analysis were intermediate (0.26-0.58). We suggest that wildlife studies will benefit from applying several identification techniques to collect data under different conditions

Geolocators reveal an unsuspected moulting area for Isle of May common guillemots Uria aalge

Data from geolocators deployed on adult Common Guillemots from a colony in southeast Scotland indicated that they normally winter in the North Sea up to 1000 km southeast of the colony. However, one bird unexpectedly moved 3000 km northeast to moult in the Barents Sea

Higher plasma oxidative damage and lower plasma antioxidant defences in an Arctic seabird exposed to perfluoroalkyl carboxylic acids

International audiencePerfluoroalkyl and polyfluoroalkyl substances (PFASs) may cause detrimental effects on physiological function and reproduction of Arctic animals. However, there is a paucity of information on the link between PFASs and oxidative stress, which can have potential detrimental effects on key fitness traits, such as cellular homeostasis or reproduction. We have examined the correlations between multiple blood-based markers of oxidative status and several perfluoroalkyl acids (i.e., with 8 or more carbons) in male Arctic black-legged kittiwakes (Rissa tridactyla) during the pre-laying period. Higher protein oxidative damage was found in those birds having higher concentrations of perfluorododecanoic acid (PFDoA), perfluorotridecanoic acid (PFTriA) and perfluorotetradecanoic acid (PFTeA). Lower plasmatic non-enzymatic micro-molecular antioxidants were found in those birds having higher concentrations of perfluoroundecanoic acid (PFUnA), PFDoA and PFTeA. Effect size estimates showed that the significant correlations between PFASs and oxidative status markers were intermediate to strong. The non-enzymatic antioxidant capacity (including antioxidants of protein origin) was significantly lower in those birds having higher plasma concentration of linear perfluorooctanesulfonic acid (PFOSlin). In contrast, the activity of the antioxidant enzyme glutathione peroxidase in erythrocytes was not associated with any PFAS compounds. Our results suggest that increased oxidative stress might be one consequence of long-chain PFASexposure. Experimental work will be needed to demonstrate whether PFASs cause toxic effects on free-living vertebrates through increased oxidative stress

Blood and feather concentrations of toxic elements in a Baltic and an Arctic seabird population

We report blood and feather concentrations of elements in the Baltic Sea and Arctic population of common eiders (Somateria mollissima). The endangered Baltic Sea population of eiders was demonstrably affected by element pollution in the 1990s. While blood concentrations of Hg were higher in Baltic breeding eiders, blood Se, As and Cd concentrations were higher in Arctic eiders. Blood concentrations of Pb, Cr, Zn and Cu did not differ between the two populations. While blood Pb concentrations had declined in Baltic eiders since the 1990s, Hg concentrations had not declined, and were above concentrations associated with adverse oxidative effects in other bird species. Inconsistent with blood concentrations, feather concentrations suggested that Pb, Zn, and Cd exposure was higher in Baltic eiders, and that Hg exposure was higher in Arctic eiders. Our study thus emphasizes the need for comprehensive evaluation of toxic element status, covering the annual cycle of a species. (C) 2016 Elsevier Ltd. All rights reserved.Peer reviewe

Integrating databases for research on health and performance in small animals and horses in the Nordic countries

In a world of limited resources, using existing databases in research is a potentially cost-effective way to increase knowledge, given that correct and meaningful results are gained

Seabirds reveal mercury distribution across the North Atlantic

Author contributionsC.A. and J.F. designed research; C.A., B. Moe, A.T., S.D., V.S.B., B. Merkel, J.Å., and J.F. performed research; C.A., B. Moe, M.B.-F., A.T., S.D., V.S.B., B. Merkel, J.Å., J.L., C.P.-P., and J.F. analyzed data; C.A., B.M., V.S.B., and J.F. sample and data collection, data coordination and management, statistical methodology; H.S. sample and data contribution and Data coordination and management; D.G., M.B.-F., F. Amélineau, F. Angelier, T.A.-N., O.C., S.C.-D., J.D., K.E., K.E.E., A.E., G.W.G., M.G., S.A.H., H.H.H., M.K.J., Y. Kolbeinsson, Y. Krasnov, M.L., J.L., S.-H.L., B.O., A.P., C.P.-P., T.K.R., G.H.S., P.M.T., T.L.T., and P.B. sample and data contribution; A.T., P.F. and S.D. sample and data contribution and statistical methodology; J.Å. statistical methodology; J.F. supervision; and C.A., B. Moe, H.S., D.G., A.T., S.D., V.S.B., B. Merkel, J.Å., F. Amélineau, F. Angelier, T.A.-N., O.C., S.C.-D., J.D., K.E., K.E.E., A.E., P.F., G.W.G., M.G., S.A.H., H.H.H., Y. Kolbeinsson, Y. Krasnov, S.-H.L., B.O., A.P., T.K.R., G.H.S., P.M.T., T.L.L., P.B., and J.F. wrote the paper.Peer reviewe

Testosterone increases siblicidal aggression in black-legged kittiwake chicks (Rissa tridactyla)

To compete for parental food deliveries nestling birds have evolved diverse behaviors such as begging displays and sibling aggression. Testosterone has been suggested to be an important mechanism orchestrating such competitive behaviors, but evidence is scarce and often indirect. Siblicidal species provide an interesting case in which a clear dominance hierarchy is established and the dominant chicks lethally attack siblings. We experimentally elevated testosterone in chicks of a facultatively siblicidal species, the black-legged kittiwake, Rissa tridactyla, and showed that testosterone-treated chicks were more aggressive toward their sibling than were control chicks. In such facultatively siblicidal species, chicks normally exhibit intense aggression only when threatened by starvation. Indeed, we found that chicks in relatively poorer condition were more aggressive than were chicks in better condition, even among testosterone-treated chicks, suggesting the action of an additional signal modulating aggression. Relatively larger siblings were also more aggressive than were relatively smaller siblings, confirming the importance of size advantage in determining dominance hierarchies within the brood. In addition, testosterone increased aggression toward a simulated predator, indicating that in kittiwakes testosterone can increase aggression in contexts other than siblicide. Testosterone promoted aggression-mediated dominance, which increased begging although testosterone treatment did not have a significant separate effect on begging. Therefore, testosterone production in the kittiwake and most likely other siblicidal species seems an important fitness mediator already early in life, outside the sexual context and not only manifesting itself in aggressive behavior but also in dominance-mediated effects on food solicitation displays toward parents

Fugleovervåkning ved etablering av nytt geodesieanlegg ved Ny-Ålesund: Årsrapport for 2015

Moe, B., S.A. Hanssen, G.W. Gabrielsen & M.J.J.E. Loonen (2016) Fugleovervåkning ved etablering av nytt geodesieanlegg ved Ny-Ålesund. Årsrapport for 2015. NINA Rapport 1228

To breed or not to breed: endocrine response to mercury contamination by an arctic seabird

International audienceMercury, a ubiquitous toxic element is known to alter expression of sex steroids and to impair reproduction across vertebrates but the mechanisms underlying these effects are not clearly identified. We examined whether contamination by mercury predicts the probability to skip reproduction in black-legged kittiwakes (Rissa tridactyla) from Svalbard. We also manipulated the endocrine system to investigate the mechanism underlying this relationship. During the pre-laying period, we injected exogenous GnRH (gonadotropin-releasing hormone) to test the ability of the pituitary to release luteinizing hormone (LH, a key hormone for the release of sex steroids and hence breeding) in relation to mercury burden. Birds that skipped reproduction had significantly higher mercury concentration in blood than breeders. Endocrine profiles of these birds also varied based on breeding status (breeders vs. non-breeders), mercury contamination and sex. Specifically, in skippers (birds that did not breed), baseline LH decreased with increasing mercury concentration in males, while it increased in females. GnRH-induced LH levels increased with increasing mercury concentration in both sexes. These results suggest that mercury contamination may disrupt GnRH input to the pituitary. Thus, high mercury concentration could affect the ability of long-lived birds to modulate their reproductive effort (skipping or breeding) according to ongoing environmental changes in the Arctic and impact population dynamics