Red Fox

The year-round food habits of lynx were studied using radio-telemetry and snow-tracking in the boreal forest of southeastern Norway. The main objectives of the study were to clarify the importance of domestic sheep and small prey species in the diet of lynx in an area with a very low density of roe deer. During the period 1995–1999, we found 193 scats and 358 kills made by lynx. Our results indicate that roe deer were the most common prey species (contributing to 83 and 34% of the biomass consumed in winter and summer, respectively), although a wide range of other species were also found, including mountain hares, tetranoids, red foxes, domestic sheep, wild reindeer, and even moose. Most of the diet was obtained by predation, although we did document several cases of scavenging. Roe deer were more important in the diet in winter than in summer, perhaps because they were easier to locate in winter as they clustered around feeding sites. In summer, domestic sheep and small prey increased in importance. Despite the very low density of roe deer in this study area, lynx seemed to still specialise on them, although domestic sheep did constitute a significant amount to their diet, especially for males and yearlings. However, the contribution of sheep to summer diet was far from that expected if their relative density was considered.

The distribution of many predators may be limited by interactions with larger predator species. The arctic fox in mainland Europe is endangered, while the red fox is increasing its range in the north. It has been suggested that the southern distribution limit of the arctic fox is determined by interspecific competition with the red fox. This has been criticised, on the basis that the species co-exist on a regional scale. However, if the larger red fox is superior and interspecific competition important, the arctic fox should avoid close contact, especially during the breeding season. Consequently, the distribution of breeding dens for the two species would be segregated on a much smaller spatial and temporal scale, in areas where they are sympatric. We tested this hypothesis by analysing den use of reproducing arctic and red foxes over 9 years in Sweden. High quality dens were inhabited by reproducing arctic foxes more often when no red foxes bred in the vicinity. Furthermore, in two out of three cases when arctic foxes did reproduce near red foxes, juveniles were killed by red foxes. We also found that breeding arctic foxes occupied dens at higher altitudes than red foxes did. In a large-scale field experiment, red foxes were removed, but the results were not conclusive. However, we conclude that on the scale of individual territories, arctic foxes avoid areas with red foxes. Through interspecific interference competition, the red fox might thus be excluding the arctic fox from breeding in low altitude habitat, which is most important in years when food abundance is limited and competition is most fierce. With high altitude refuges being less suitable, even small-scale behavioural effects could scale up to significant effects at the population level.

Zusammenfassung Jeweils rund 30 Vorderextremitätenpaare vom Goldschakal und vom Rotfuchs wurden mor-phologisch und osteometrisch untersucht. An den vier untersuchten Skelettelementen, Scapula, Humerus, Radius und Ulna konnten arttypische Unterschiede festgestellt werden. Während alle Formelemente und Maße der Scapula eine Artdifferenzierung zuließen, unterschieden sich die Langknochen vor allem im Bereich der Gelenkkörper. Die Ausbildung des Ellbogengelenkes beim Goldschakal weist im Vergleich zum Rotfuchs auf eine größere Bewegungsfreiheit für Pronation und Supination hin. Einfache univariat und bivariat generierte Diagramme mit den erhobenen Messwerten lassen bereits eine Trennung der beiden Arten erkennen. Für eine wei-tere Differenzierung der beiden Arten wurde ein artspezifischer Größenunterschied eliminiert, indem die osteometrischen Daten prozentuell zu einer gemittelten Kopf-Rumpflänge in Bezie-hung gesetzt, log-transformiert und die Ergebnisse mittels Mann-Whitney U-Test verglichen wurden. Ein Großteil der verfügbaren Daten ermöglichte sehr gute Differenzierung der beiden Arten. Multivariate Varianzanalysen (MANOVA) und Diskriminanzanalysen von Messstrecken-kombinationen ergaben eine zum Teil sehr hohe Trennkraft zwischen den Arten und manche Merkmalskombinationen wurden zu 100 % den vorhergesagten Gruppen zugeordnet.

The discovery in 2008, during an archaeological survey carried out on the Digges Islands (southern shores of Hudson Strait, Nunavut), of a fox den (Vulpes vulpes) with associated bones allow us to better understand the feeding habits of the red fox in an arctic periglacial context. The bones, essentially representing diverse bird species, were collected near the entrance and exit points of the still active den. Bird species include the Canada goose (Branta canadensis), the snow goose (Chen caerulescens) and the murres (Uria lomvia). The majority of these birds was caught during the month of July 2008 by the foxes, especially during their summer migration phase. The den being still active, fox cubs were present during our passage. It is planned to make a brief return over the coming years to see if more bones will have accumulated since our
last visit.

This paper is a first attempt to investigate the variability in reindeer-procurement strategies in Upper Palaeolithic sites by means of sex ratios, as reflected by osteometrical data. For this purpose the “Variability Size Index” method is employed. The idea behind the analysis is that sex ratios in reindeer (but also in red deer and in bovids) were mainly determined—as they are in modern populations—by the reproductive biology of the animals and not by environmental conditions. Thus, any deviations from these ratios must be explained in terms of behavioural/cultural variables. The faunal material for the study comes from sites in southwest France, Switzerland and southern Germany. During the Upper Palaeolithic females dominate in all assemblages, but a clear variability can be seen: some sites show sex ratios similar to those found in Palaeolithic carnivore dens, whereas other sites show somewhat higher frequencies of bulls. The variation in the sex ratios of reindeer among Upper Palaeolithic sites cannot be explained by either their chronological position or topographical location, but it is more probably a result from seasonal differences in reindeer-procurement. Thus generalizations about the exploitation of reindeer or other prey species based on results of a single site or layer of a site will mask the variability in the subsistence strategies which existed either during the Upper Palaeolithic or, at a finer scale, even during the Magdalenian.

Climate change has been characterized as the most serious threat to Arctic biodiversity. In addition to gradual changes such as climate warming, extreme weather events, such as melting temperatures in winter and rain on snow, can have profound consequences for ecosystems. Rain-on-snow events lead to the formation of ice layers in the snow pack, which can restrict access to forage plants and cause crashes of herbivore populations. These direct impacts can have cascading effects on other ecosystem components, often mediated by trophic interactions. Here we document how heavy rain in early winter, leading to the formation of a thick layer of ice, was associated with dramatic mortality of domestic reindeer on Yamal Peninsula, Russia. In the subsequent summer, breeding of two boreal generalist predators, red fox and Hooded Crow, was recorded for the first time in a monitoring area in the Low Arctic tundra of this region. We suggest that the resource pulse created by the abnormally high reindeer mortality and abundance of carrion may have facilitated these breeding events north of the known breeding range of the two species. Our observations provide an example of how specific emergent weather events may indirectly pave the way for more abrupt, although possibly temporary, species range changes. RÉSUMÉ. Le changement climatique a été caractérisé comme la plus grande menace à la biodiversité de l'Arctique. En plus des changements graduels comme le réchauffement climatique, les phénomènes météorologiques extrêmes comme les températures positives en hiver et la pluie tombant sur la neige peuvent avoir de profondes conséquences sur les écosystèmes. La pluie tombant sur la neige mène à la formation de couches de glace dans le manteau neigeux, ce qui peut avoir pour effet de restreindre l'accès aux plantes fourragères et d'entraîner l'effondrement des populations herbivores. Ces impacts directs peuvent avoir des effets en cascade sur d'autres composantes des écosystèmes, et cette propagation passe souvent par des interactions trophiques. Dans cette communication, nous décrivons comment une pluie abondante en début d'hiver, menant à la formation d'une couche de glace épaisse, a été accompagnée par une mortalité dramatique des rennes domestiques dans la péninsule de Yamal, en Russie. L'été suivant, la reproduction de deux prédateurs boréaux généralistes, soit celui du renard roux et celui de la corneille mantelée, a été enregistrée pour la première fois dans une aire d'étude de la toundra du Bas-Arctique de cette région. Nous suggérons que l'abondance de ressources créée par le taux de mortalité anormalement élevé de rennes et l'abondance de charognes aurait pu susciter ces épisodes de reproduction au nord de l'aire de répartition connue des deux espèces. Nos observations fournissent un exemple selon lequel des phénomènes météorologiques émergents particuliers peuvent, indirectement, ouvrir la voie à des changements plus abrupts en matière d'aire de répartition des espèces, bien que ces changements puissent être temporaires. Mots clés : renard arctique (Vulpes lagopus); renard roux (Vulpes vulpes), corneille mantelée (Corvus cornix); renne domestique; englacement du sol; pluie tombant sur la neige; réseau alimentaire; agrandissement de l'aire de répartition Traduit pour la revue Arctic par Nicole Giguère. РЕЗЮМЕ. В настоящее время, изменения климата представляются наиболее серьезной угрозой для биоразнообразия Арктики. В дополнение к постепенным изменениям, таким как потепление климата, экстремальные погодные явления (зимние потепления до температуры таяния или жидкие осадки на снежный покров) могут иметь серьезные последствия для экосистем. Погодный феномен «дождь-на-снег» приводит к формированию слоев льда в снежном покрове, что может ограничивать доступ к кормовым растениям, и явиться причиной падения популяций

The red fox Vulpes vulpes is usually classified as being territorial, dispersing or transient. Past studies have focused almost exclusively on territorial or dispersing foxes, leaving transient foxes out of the analysis. In this paper, we present spatial-statistical methods for the classification of free-ranging foxes, using 95% fixed kernels and 100% minimum convex polygons. By means of these procedures we classify individual foxes on the basis of their spatial behaviour, using home-range size and home range shift. Also, we ...