Attracting endangered species to 'safe' habitats: responses of fairy ternsto decoys

The New Zealand fairy tern (Sterna nereis davisae) is considered an endange red subspecies. The aims of this study were to quantify fairy tern response s to decoys and sound recordings and determine the viability of decoys as a technique for re-establishment of this species in protected habitat. Sixte en decoy trials were conducted in an area suitable for nesting from 9 Septe mber to 2 October 1999 at Papakanui Spit, New Zealand (36 degrees 26'S, 174 degrees 13'E). The decoy models were effective in attracting fairy terns t o a specific area. There was a significant effect due to decoys with >80% o f landing episodes occurring in the decoy plots. There was no effect due to individual plots. A planned contrast between decoys with and without recor dings showed no significant difference. The behaviour of the fairy terns to wards the decoys paralleled live tern interactions, e.g., erect postures, o ne aggressive response and a possible courtship feeding. Fairy terns appear to be less social than other members of the Laridae family (although their population numbers make the level of gregariousness difficult to determine ). Despite low numbers, the response to the decoys was highly significant. We suggest that decoy techniques could be used as a simple and effective ma nagement tool for a wide range of group-living species. Such techniques wil l become particularly important as the availability of suitable habitat dec lines owing to anthropogenic effects. Finally, regardless of whether the at traction of fairy terns towards these decoys encourages residence and nesti ng in this area, the effectiveness of attracting terns to a specific locati on results in a safe and efficient means of trapping adults away from the n est and/or outside the breeding season.