Since human settlement of New Zealand, at least 51 bird species have become extinct, and many others have become either locally extinct or endangered. Of the 51 extinctions, 21 species survived till the arrival of Europeans before they too became extinct. While the exact cause of a bird species decline to extinction is often debated, a number of contributing factors including loss of habitat, habitat fragmentation, competition, predation and avian diseases brought in with European introduced birds are likely to have played a part in their demise.
During the period 1992 to 2013 there have been 53 species recorded in the Styx Mill Conservation Reserve. Of these 34 are resident species, 10 seasonal visitors and 9 have been vagrants..
The tables below provide a list of some of the bird species that can be found in the Styx catchment. Further information about the status and habitat requirements of wetland birds and bush birds can be found on other pages.