But for a chance conversation in the Coed y Capel hide on Big Garden Birdwatch day, Mark Leonard's excellent photo of an otter swimming in the pool below the dam (see the Gallery) would have been known only to Mark himself and his family.
Apart from proving that otters are present at Vyrnwy, this photo helps enormously in making the case for wildlife on our reserve. It's a great example of the sort of valuable record that our visitors must be making all the time. Reserve staff are out and about every day, it's true, but they are a tiny few compared with the thousands of visitors who come to Vyrnwy.
If you see something that looks interesting to you - even better, if you manage to get a photo - whether it's an otter, an osprey, a bird you can't identify, or some unusual behaviour, do please let us know. Call in to the shop, or email us (vyrnwy@rspb.org.uk).
We promise we won't mind if your great discovery is old hat to us, we'll probably be really grateful for the record, and who knows, you may be giving us a first for the reserve that we would have missed otherwise.
Are you a member of the RSPB? Nature is amazing, help us keep it that way. To join contact me on roger.whiteway@rspb.org.uk