Behavioural responses and attraction of New Zealand sea lions to on-land female decoys

Abstract

Using decoys to attract gregarious animals is a common management practice, but rarely used for pinnipeds. We investigated the behavioural responses of New Zealand (NZ) sea lions, Phocarctos hookeri, at Sandy Bay, Enderby Island, to determine whether decoys can attract female sea lions and so could be useful for the establishment of new colonies. We deployed decoys near existing breeding aggregations for 4 hours at a time. One or a group of three artificial decoys, made of white fabric, attracted up to 54% of females coming ashore, of which 73% tame close enough to sniff the decoys. Up to 62% of males coming ashore within 15 m either side of these decoys moved towards them. A single taxidermied female NZ sea lion did not attract females significantly more often than a single fabric one, but was investigated as if alive by males. It appears that female NZ sea lions are attracted to decoys by their colour, at least when located close to an existing group of females. A technique using decoys could be trialled to direct recolonising females to suitable pupping sites. © 2010 The Royal Society of New Zealand.