Am. Midl. Nat. (2021) 185:249–259 Seasonal Space Use and Movement of a Grey Wolf (Canis lupus) in a Protected Archipelago in Lake Superior, Ontario ASHLEY A. D. MCLAREN 1 AND BRENT R. PATTERSON 2 Ontario Ministry of Natural Resources and Forestry, Wildlife Research and Monitoring Section, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario, Canada, K9L 1Z8 ABSTRACT.—Data on movement of grey wolves (Canis lupus) in island systems is largely restricted to coastal environments and little is known about their space use and movement in freshwater archipelagos. We used data from a GPS-collared wolf in a protected archipelago in Lake Superior, Ontario to examine broad seasonal patterns in space use, movement, and activity. Over approximately 1 y of monitoring, the wolf made 190 crossings between islands and showed more extensive use of the archipelago during the nonwinter season. When ice was present in the archipelago, the mean weekly inter-island crossing rate of the wolf (6 SE) was 6.08 6 1.31, with crossings largely restricted to the interior islands bounded by ice, compared to 2.85 6 0.45 during the open water season. Mean wolf activity was highest in the nonwinter season, but movement rates were comparable across seasons. Our study is the first to document wolf movements in a freshwater archipelago with seasonal ice cover and supports data collection at fine temporal scales to better understand trends in wolf space use and movement at small spatial scales. INTRODUCTION Mammalian carnivores are relatively rare on islands (Alcover and McMinn, 1994). Though some insular carnivores are endemic (Wilting et al., 2006; Rick et al., 2009), the presence of mammalian carnivores on many islands is more dynamic and dependent on natural movements to and from the mainland (Miller and Reintjes, 1995; Doup´ e et al., 2007; Mu ˜ noz- Fuentes et al., 2010; Allen et al., 2018). For grey wolves (Canis lupus), colonization of islands from nearby mainland populations has occurred by migration across ice bridges (Nelson et al., 2011; Plumer et al., 2016) or by swimming from the mainland and among nearby inhabited islands (Klein, 1995; Darimont et al., 2004; Mu˜ noz-Fuentes et al., 2010). Although some suggest water can be a barrier to wolf movement (Klein, 1995; Paquet et al., 1996; Person et al., 1996), wolves have been found on isolated islands 13 km off the coast of British Columbia (Darimont and Paquet, 2002), indicating an ability to swim long distances. Most studies on the movement of wolves among islands have been restricted largely to marine coastal environments and few studies have explicitly examined wolf movements in a freshwater archipelago system, particularly in boreal regions where occasional ice cover is more likely to facilitate inter-island movements. This includes the long-term research on wolves in Isle Royale National Park (1959–present) in northern Lake Superior (see Vucetich and Peterson, 2004), but wolves in that study system typically limit their movements to the large main island, which comprises over 98% of the total land area of the park; though, recent findings indicate some use of small offshore islands by wolves (Romanski et al., 2020). Additionally, for noncoastal areas, reports of wolves swimming are often related to accounts of predation attempts rather than general movements (Mech, 1970; Nelson and Mech, 1984; Paquet and Brook, 2004; Jordan et al., 2010; Kiss et al., 2010; Nichols, 2015; but see Coscia, 1993; Paquet et al., 1996; Theberge, 1998). There remains a lack of data on wolves in 1 Corresponding author: E-mail: ashley.mclaren@ontario.ca 2 E-mail: brent.patterson@ontario.ca 249