Abstract :
Translocation, the intentional release of a species in a new location, plays an important role in the conservation of endangered species. Consequently, there is a critical need for research on factors affecting the outcome of translocation attempts. This study addresses the hypothesis that founder groups will do better if they are made up of individuals that are familiar with one another. The hypothesis is based on research on birds showing that familiarity between mates and neighbours leads to lower aggression and higher reproductive success. Our test involved a translocation of the North Island saddleback Philesturnus carunculatus rufusater, a New Zealand forest bird restricted to islands free of mammalian predators. We created two founder groups of 18 birds each, one made up of birds from a single small forest patch, and including five known pairs, and the other a mixture of birds from several patches, with no pairs. We released the groups in different parts of an island, and assessed the effects of familiarity on survival, dispersal, pair bonding, and reproduction. The two groups showed similarly high survival, and both dispersed widely. Pair bonds formed more quickly among the familiar birds, even though only one of the five original pairs stayed together after translocation. While pairing among unfamiliar birds tended to be delayed, they achieved a similarly high rate of pairing by the start of the breeding season, and reproductive output was similar for familiar and unfamiliar pairs. We therefore found no evidence that using familiar individuals would improve the outcome of bird translocations. We note that familiarity could be more important with other species and/or in other circumstances. However, we also note the potential costs of using familiar individuals.
