Winter home range fidelity and extraterritorial movements of Arctic fox pairs in the Canadian High Arctic

Abstract

The sociality of the Arctic fox has been extensively studied during the breeding season, so that its summer territorial and generally monogamous social systems are now well described. A key knowledge gap remains, however, during the winter season, when logistic challenges preclude detailed observation of individuals. We have studied the socio-spatial winter dynamics of Arctic fox pairs to determine: (1) winter fidelity of Arctic fox pair mates to their summer home range; (2) the degree to which extraterritorial movements are simultaneous between pair mates; and (3) spatial proximity between pair mates when they perform simultaneous extraterritorial movements. To meet these objectives, 15 Arctic fox pairs from Bylot Island (Nunavut, Canada) were tracked during at least one winter in 2007-2011, using Argos satellite collars, for a total of 21 pair-years. Arctic foxes were generally faithful to their summer home ranges during winter, but some variation occurred among pairs. The degree of territory fidelity was highly correlated between pair mates. When foxes did extraterritorial movements, they performed excursions that were short in duration and generally not synchronized among pair mates. When pair mates were outside the territory at the same time, they did not travel together and rather foraged independently. We discuss some ecological implications of our findings, and suggest that different patterns may be observed in other Arctic fox populations. If such is the case, replicating our study in other parts of the species range will allow productive hypothesis testing regarding the determinants of Arctic fox winter sociality.

Arctic fox dispersal from Svalbard to Canada: one female’s long run across sea ice

“…Norén et al (2011) used population genetic analyses to infer that the immigration rate is higher than the emigration rate in Svalbard and that Arctic foxes in Svalbard immigrate from lemming-dominated ecosystems in North America and Siberia. This is in line with the suggestion that long-distance movements are more common among the lemming ecotype (low food availability after a lemming peak acting as a dispersal trigger) than in the coastal ecotype (Braestrup 1941;Pullainen 1965;Wrigley & Hatch 1976;Roth 2002;Pamperin et al 2008;Tarroux et al 2010;Norén et al 2011;Lai et al 2015;Rioux et al 2017). There is limited evidence to suggest that in some den areas in Svalbard some adult offspring may remain in their natal areas to help rear siblings (Norén et al 2012).…”

“…In the last 20 years, satellite telemetry in North America has revealed heretofore uknown details of the spatial ecology of Arctic foxes (Follmann & Martin 2000;Pamperin et al 2008;Tarroux et al 2010;Lai et al 2015;Rioux et al 2017). Such studies have demonstrated the extensive use of sea ice as a foraging habitat and as a platform for exploration and dispersal.…”

Derivation of predator functional responses using a mechanistic approach in a natural system

“…We estimated acquisition rate of nest content (eggs or chicks) by using the daily survival rate of nests ( dsr ), the total number of nests found in the study plot ( N tot ), the number of foxes foraging in the plot ( N fox ) and the proportion of nests predated by foxes ( P fox ). Since foxes establish territorial pairs on Bylot (Rioux et al 2017), we assumed that 2 foxes were foraging in the study plot. We also considered that foxes were responsible for 100% ( n = 19) and 81% ( n = 25) of the failed sandpiper and passerine nests, respectively, as indicated by camera monitoring (McKinnon and Bêty 2009; Royer-Boutin 2015).…”

“…Predator speed A total of 16 foxes (7 females and 9 males) were equipped with a GPS collar (Radio Tag- as described in (Rioux et al, 2017). GPS fix intervals were fixed at 4 minutes (360 fixes per day), and data were downloaded to a hand-held receiver using UHF transmission.…”

Foreword to Supplement 1: research on a polar species—the Arctic fox

“…Electronic devices, however, now offer the opportunity to study elusive wildlife in the most extreme conditions of cold and darkness. A study with a winter perspective was the analysis of spatial movements by Arctic foxes around Bylot Island (Canada) by Rioux et al (2017). Using satellite telemetry, they found that pairs of foxes remain in or close to their home range during winter.…”