Mallard on garden pond?

[werdnal]

Last week our neighbour said he had been very surprised to find a duck on his garden pond. He was sorry he'd gone into the garden and disturbed it and it flew off. We just assumed it was passing through and thought no more of it, until 5 minutes ago, we heard a duck flying over, and she (we think its female as very brown to look at), dropped like a stone straight onto his pond. Neighbour has quite a large garden (half an acre at a guess), but the pond is only about 15ft across and a couple feet deep. We are in a very rural spot, with heathland not far away, but we don't know of any other large bodies of water nearby. Is it unusual for a wild duck to use such a small pond? Our guess is she could be nesting somewhere in the vicinity and using the pond for a daily visit, drink, wash and brush up etc. Wonder if we'll see her strolling down the lane in a few weeks time with a brood of ducklings in tow!

Any thoughts please?