Perhaps the most important rule is that you have to be certain of the correct identification of a plant or animal that you are going to record. If in doubt, leave it out! However, this doesn't mean that you have to be an expert who can tell apart a near-identical willow tit from a marsh tit. In fact, recording familiar species such as house sparrows, rabbits or bluebells, is just as valuable as recording ones that are harder to find and identify. Often, more commonplace species do not get recorded at all, which can cause lots of problems down the line if they start to become more scarce; we then find that we have very little data about how abundant they used to be (the decline of the house sparrow is an excellent case in point).
If you do find something that you think might be unusual, or you're not quite sure the identity of, make notes about its appearance and behaviour, and anything else that might help someone else to clarify what it is. Even better, try to take a photo! You can send your photos (or questions/notes) to NWT's Wildline
and we will do our best to help identify what you have seen.