Drivers of seabird population recovery on New Zealand islands after predator eradication

Published source details Buxton R.T., Jones C., Moller H. & Towns D.R. (2014) Drivers of seabird population recovery on New Zealand islands after predator eradication. Conservation Biology, 28, 333-344.
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Summary

Control mammalian predators on islands for seabirds

A review in 2014 across islands around New Zealand (Buxton et al. 2014) found that after eradicating mammalian predators most populations of seabirds increased, particularly small and already increasing populations, and some island recolonizations occurred. Following mammal eradication, more seabird colonies with smaller size pre‐eradication increased in abundance compared to larger colonies (73% of colonies <25 birds increased post-eradication; 100% of 25–100- bird colonies; 55% of 100–5,000-bird colonies; 25% of colonies >5,000 birds). More colonies increased in abundance post-eradication if they were already increasing or stable before eradication (75–81%) compared to declining colonies (33%). Recolonization completeness decreased with the distance to a source population (1 km distance: 90% of seabird species recolonisation; 2–9 km: 50%; 10–24 km: 43%; 25–60 km: 10%; 61–200 km: 13%; over 200km: 15%). Recolonization was also more complete on islands with more existing breeding seabird species, and with less modified habitat (see original paper for details). The study analysed data from 41 islands where all non‐native mammalian predators had been eradicated in 1936–2011. Seabird population data were collated from literature and interviews. The data included seabird species of many different groups, including petrels, shearwaters, penguins, gulls, terns and shags.