A mystery

Strange happenings are afoot at Screwham Hall. On opening the blinds this morning there was water on the patio by my fish pond. Fearing something had fallen in I noticed bird poo. It was then that I noticed on the path between the pond and the conservatory some tadpoles, 14 in total. I noticed one wriggle so manage to wash most back into the pond where they seemed no worse for their troubles. There were more tadpoles on the patio but sadly they were past saving. I did wonder heron but the poo isn't big enough. I've heard of blackbirds eating tadpoles but whatever did it why catch them without eating them? Whatever it was seems to have spooked my fish, unless some have been taken, and this happened once before and at that time the culprits were gulls and my money is on them this time despite the poo not matching what comes from a gulls rear end.