OK, it’s been a long long time since I looked at it, in fact not since 1992 (wow, am I that old? Oh heck, yes… my kids have grown up and left home, sheesh). Since then there has been a new act (1994), so my understanding is not as certain as I thought! NZ no longer applies a “fair use” provision per the Berne Convention, but instead has something called a “fair dealing” provision, which is outlined in brief in the following guide:
https://www.copyright.co.nz/Downloads/Assets/5212/1/fact-sheet:-fair-dealing-in-new-zealand.pdf
(but to be honest, I don’t see a difference to “fair use”)
So to re-iterate, in New Zealand at least, you don’t “copyright something”, and there is no question IF someone else has copyrighted something, because copyright is AUTOMATIC. A copyright statement is merely the implicit assertion of that right, a reminder if you will that you should think twice before using it unfairly because the owner would likely defend their copyright. Creative Commons licenses seem to come under the “blanket licensing” aspect mentioned in that document, but again that doesn’t preclude you from using in a “fair dealing” manner. Which brings me to the big point, it is difficult to ascertain exactly what fair dealing (or fair use) is, and I think it is best to err on the side of caution/respect, and just try not to copy!
One thought that occurs to me, is that “copy for personal study” might be what a new user in iNat is thinking they are doing, ie not being fully aware that their observations are public domain, rather thinking that the observation is a place for them to make notes and “keep copies for personal use”.