Here are our data sources for your reference:
Domestic cats
http://www.wspa.org.nz/latestnews/2011/NZ_survey_a_nation_of_animal_lovers.aspx
http://www.doc.govt.nz/publications/conservation/native-animals/birds/saving-our-kiwi/threats-to-kiwi/
Dowding, J. E.; Murphy, E. C. 2001. The impact of predation by introduced mammals on endemic shorebirds in New Zealand: a conservation perspective. Biological Conservation 99: 47-64.
Veitch, C.R. 1985. Methods of eradicating feral cats from offshore islands in New Zealand. ICBP Technical Publication 3: 125-141
van Heezik, Y. et al Do domestic cats impose an unsustainable harvest on urban bird populations? Biological Conservation 143 (2010) 121–130
Metsers, E.M. et al Cat-exclusion zones in rural and urban-fringe landscapes:how large would they have to be? Wildlife Research, 2010,37,47–56
http://www.huffingtonpost.com/2012/08/08/kitty-cam-uga-research-national-geographic-killing_n_1757070.html
Adamec, R.E. Wedge-tailed Shearwater: David G. Smith 1976. The interaction of hunger and preying in the domestic cat (Felis catus): an adaptive hierarchy? Behavioral Biology 18: 263-272
American Bird Conservancy, Domestic Cat Predation on Birds and Other Wildlife.
Feral cats
http://rnzspca.org.nz/saving-lives/what-is-saving-lives
Dauphine, N et al. Pick One: Outdoor Cats or Conservation. The Wildlife Professional, Spring 2011 pp 50-56.
Lohr, C.A. et al.; Costs and Benefits of Trap-Neuter-Release and Euthanasia for Removal of Urban Cats in Oahu, Hawaii. Conservation Biology Article first published online: 25 Sep 2012 DOI: 10.1111/j.1523-1739.2012.01935.x
Butchart, S.H.M. Red List Indices to measure the sustainability of species use and impacts of invasive alien species. Bird Conservation International (2008) 18:S245–S262.
Medina, F.M et al. A global review of the impacts of invasive cats on island endangered vertebrates. Global Change Biology (2011), doi: 10.1111/j.1365-2486.2011.02464.x
Powlesland, R.G., Roberts, A., Lloyd, B. D. & Merton, D.V. 1995. Number, fate and distribution of kakapo (Strigops habroptilus) found on Stewart Island, New Zealand, 1979 – 92. N.Z.J.Zool. 22: 239 – 248.
Dowding, J. E.; Murphy, E. C. 1993. Decline of the Stewart Island population of the New Zealand Dotterel. Notornis 40: 1-14.
Harper, G.A. Habitat selection of feral cats (Felis catus) on a temperate, forested island. Austral Ecology Volume 32, Issue 3, pages 305–314, May 2007
http://www.doc.govt.nz/about-doc/news/media-releases/2010/cat-nabbed-raiding-the-mothership/
Fitzgerald, B.M. 1988. Diet of domestic cats and their impact on prey populations. In: Turner, D.C.; Bateson, P. (Editors), The domestic cat: the biology of its behaviour, pp. 123-147. Cambridge University Press, Cambridge, U.K. 222 pp.