Professor Bruce Clarkson is currently delivering the Charles Fleming Memorial Lecture Series – see http://royalsociety.org.nz/whats-happening/our-events/urban-ecological-restoration-the-new-frontier/ for the programme. He has also been interviewed by Jesse Mulligan on National Radio: http://www.radionz.co.nz/national/programmes/afternoons/audio/201842483/how-to-bring-nature-back-to-cities
It’s an excellent overview and puts our predator control efforts in context. Meanwhile if you would like to know more about rats in particular, here’s an interview with Predator-Free Hamilton member and Landcare Research scientist John Innes:
http://www.radionz.co.nz/national/programmes/summer-days/audio/201829629/everybody-has-rats
Happy trapping!