Just published in Royal Society Open Science is a paper with the provocative title ‘Rat eradication comes within a whisker! A case study of a failed project from the South Pacific’. Written by Bill Amos and Michael Brooke of the Department of Zoology, Hazel Nichols of Liverpool John Moores University and Tom Churchyard of RSPB, it addresses the failure of the attempt to eradicate Polynesian rats from Henderson Island in the South Pacific. In the absence of any signal of poison resistance or of an untimely introduction of rats from other islands in the region, the authors attempt to estimate the number of rats to which the Henderson population was reduced by the eradication attempt. By comparing allele frequency amongst rat samples obtained before and after the failed attempt, they suggest a population bottleneck of about 60-80 rats. Not bad given a starting population of 50,000 - 100,000 on an island of 43 km2 – but not good enough.

http://rsos.royalsocietypublishing.org/content/3/4/160110

http://www.sciencemag.org/news/2016/04/how-these-island-rats-survived-75-metric-tons-poison

http://news.nationalgeographic.com/2016/04/160419-rats-exploded-poison-henderson-island/