Laura Molles and her colleagues attempted such a translocation to a managed area surrounded by continuous forest: Ngapukeriki is located in the Bay of Plenty on the North Island of New Zealand. The conservationists decided to use social attraction in order to encourage the kokakos to stay in the target area after release. For the kokako the presence of resident individuals indicates that they are likely to find the right habitat conditions, food resources and potential mates in the vicinity.
But what if there are no resident kokako yet in the target area? One answer is to trick the birds, giving them the impression that there are plenty of other kokako around. In this case three social attractants were used simultaneously: 1. releasing many birds at the same time; 2. keeping a pair of kokako in an aviary at the release site and 3. using playback of kokako song as ‘acoustic anchor’.
Acoustic anchoring is the most exciting one of these tactics as it had never before been used in translocations of terrestrial birds. Recordings for the playback were made in the source population so that the translocated birds could be exposed to the song of their former neighbours, singing and calling in their familiar ‘dialect’. Three kokako held in the aviary at the release site responded positively to a trial playback.
All this is good evidence that acoustic anchoring is likely to have contributed significantly to the success of this translocation. On the other hand this study was not designed to prove the effectiveness of acoustic anchoring on its own but to find out if the combination of the three social attractants would lead to a successful establishment of a population. The re-introduction of kokako to Ngapukeriki can definitely be regarded as a success as the first young already fledged in 2006. “And every year since, the kokako of Ngapukeriki have bred successfully and the population continues to grow” says Laura.
Laura Molles and her team have already put that into practice in a translocation of Tui to Banks Peninsula in 2009. The acoustic anchoring technique has also been trialled on robins, whiteheads and in two further kokako translocation projects.
This article is based on:
Molles, L.E., Calcott, A., Peters, D., Delamare, G., Hudson, J.D., Innes, J., Flux, I., Waas, J. 2009. 'Acoustic anchoring' and the successful translocation of North Island kokako (Callaeas cinerea wilsoni) to a mainland management site within continuous forest. Notornis 55(2): 57–68.
Photos from kokakorecovery.org.nz with kind permission from Laura Molles.