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 for ce birds off of nests. We examined how parental nest attendance by lesser s now geese (Chen caerulescens caerulescens) affected (i) foraging behaviours of arctic foxes (Alopex lagopus) and (ii) egg loss by geese exposed to arc tic foxes at a large goose colony on Banks Island, N.W.T., Canada. Unattend ed nests and nests attended by single females suffered much greater egg los s to foxes than nests attended by paired geese. This resulted from foxes at tacking unattended nests and single females far more frequently than expect ed by chance and from geese associated with such nests offering little or n o 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 reducin g egg loss to arctic foxes, but it may play an even greater role in reducin g egg loss to arctic foxes in small colonies or during colony formation, wh en the ratio of predators to nests is generally high.