Sparrows Nest?

Most days I see this little sparrow sitting on the drainpipe on the corner of our house.

When I was out for a walk this afternoon I spotted something swimming in the stream - it could have been a rat, a mink or maybe even an otter?  When I got home and mentioned this to thechimp, he told me that an otter had been seen nearby - so maybe it was an otter - I’d like to think so