Deterring arctic fox predation: the role of parental nest attendance by lesser snow geese

High parental attendance at nests can improve nesting performance in birds by shortening the nesting period and by deterring predators that do not force birds off of nests. We examined how parental nest attendance by lesser snow geese (Chen caerulescens caerulescens) affected (i) foraging behaviours of arctic foxes (Alopex lagopus) and (ii) egg loss by geese exposed to arctic foxes at a large goose colony on Banks Island, N.W.T., Canada. Unattended nests and nests attended by single females suffered much greater egg loss to foxes than nests attended by paired geese. This resulted from foxes attacking unattended nests and single females far more frequently than expected by chance and from geese associated with such nests offering little or no resistance to foxes. Paired geese, in contrast, were avoided by foxes and also showed greater resistance to foxes than single females and unattended nests. Nest attendance by male geese can therefore be important in reducing egg loss to arctic foxes, but it may play an even greater role in reducing egg loss to arctic foxes in small colonies or during colony formation, when the ratio of predators to nests is generally high.