I had a blutit nest in a very old nesting box at the top of a very old bird table,completely ignoring new nest boxes.The wood legs are rotten and I had propped it up with a view to remodelling it but it was very precarious so I had to wait until the parents were off foraging and keep nipping out to try and make it more secure.It wouldn't have taken much for the wind or a child to topple it.They didn't seem to mind me hovering and the babies fledged safely.
Its way too cold and wet for outdoors recently,which is probably a good thing as I,m plodding away with inside stuff.but I,m keeping an eye out for frogspawn.I usually put it in a bucket indoors if its likely to freeze,then put it back in the pond later in spring.