As I said, I don't think it's a question of certainty. We never have certainty in science. In the environmental field we're quite used to operating with a degree of uncertainty. But if you don't know if that species even nests there.... The piping plover example was very instructive. There was habitat that looked like perfectly good habitat, but we found they never used it.
Evidence of meeting #9 for Environment and Sustainable Development in the 40th Parliament, 2nd Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was sara.
A recording is available from Parliament.