Polar Biol (2008) 31:249–253 DOI 10.1007/s00300-007-0378-8 123 SHORT NOTE Dispersion during the moult haulout of southern elephant seals at the Courbet Peninsula, Iles Kerguelen T. H. Setsaas · M. N. Bester · J. H. van Niekerk · J. P. Roux · G. J. G. Hofmeyr Received: 18 October 2006 / Revised: 25 September 2007 / Accepted: 2 October 2007 / Published online: 18 October 2007  Springer-Verlag 2007 Abstract We studied the dispersion of 4-year-old southern elephant seals (Mirounga leonina) along a 75.5 km coastal area at the Courbet Peninsula, Iles Kerguelen, relative to their birth site when they were ashore to moult in early 1984. The seals were mostly faithful to their natal sites, but availability of suitable moulting habitat (e.g. wallows, veg- etated areas) inXuenced seal dispersion. As moult pro- gressed, the seals moved farther away from their initial moult sites and natal sites, but remained largely on the east- erly beaches of the Courbet Peninsula. This behaviour would facilitate mark-recapture estimates of age and sex speciWc survival. Keywords Southern elephant seal · Mirounga leonina · Four-year-olds · Dispersion · Moulting · Site Wdelity · Iles Kerguelen Introduction Southern elephant seals (Mirounga leonina) are pelagic for about 75% of their lives, returning ashore only to breed, moult and rest (Carrick et al. 1962). All seals older than pups (i.e. >1 year old) haul out for up to a month or more to moult in summer and autumn (November–April; Carrick et al. 1962; Condy 1979; Kirkman et al. 2003). Immature seals may haul out on one or more occasions during autumn and winter (February–September) for a few days or weeks at a time, until they are sexually mature (Carrick et al. 1962; Kirkman et al. 2001). The timing of these events is highly synchronous between years and populations (Carrick et al. 1962; Condy 1979; Hindell and Burton 1988). Seals often return close to their birth site for these haulout events (Nicholls 1970; Hindell and Little 1988), but long-distance movements to localities other than their natal islands have also been recorded (e.g. Burton 1985; Bester 1988; Guinet et al. 1992; van den HoV 2001). Several studies show that southern elephant seals have a high degree of Wdelity to their birth site when hauling out to breed (Nicholls 1970; Hofmeyr 2000). Similar results have also been found for immature seals when hauling out to moult or rest during the year (Nicholls 1970; Hofmeyr 2000). However, other studies also show that some south- ern elephant seals do not return preferentially to their birth site when ashore to moult (e.g. Macquarie Island, Nicholls 1970; and Heard/Kerguelen Islands, Burton 1985). These are the exceptions rather than the rule (Bester 1988) and more likely to involve males (cf. Burton 1985). Females tend to return closer to their birth site than males when ashore to breed (Nicholls 1970), whilst no diVerence is found between the sexes during resting and moulting haulouts (Nicholls 1970; Hofmeyr 2000). This implies that males and females have the same requirements T. H. Setsaas · M. N. Bester (&) · J. H. van Niekerk · G. J. G. Hofmeyr Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, 0002 Pretoria, South Africa e-mail: mnbester@zoology.up.ac.za T. H. Setsaas Department of Biology, Norwegian University of Science and Technology, Realfagsbygget, 7491 Trondheim, Norway J. P. Roux CNRS Laboratoire de Zoologie, Faculté des Sciences, USTL, Montpellier, France J. P. Roux Lüderitz Marine Research, Directorate of Resource Management, Namibian Ministry of Fisheries and Marine Resources, P.O. Box 394, Lüderitz, Namibia