So earlier I was out on the balcony. I heard a squawk and then a splat. There's a walkway right below the balcony - I looked down and there was a very dead fish lying on the concrete. Short of it being a very localised Fortean event a herring gull must have plucked it from the canal, got startled (I didn't see or hear any other birds) and dropped its catch. The fish has gone now, hopefully snatched by one of the estate cats. Earlier still, I found what I thought was a blackened bit of dead moss, a crusty thing about as big as the ball of my thumb. I trod on it by accident and it went into shiny jet fragments, shards of beetle wing cases, like insect shrapnel. As far as I can guess a crow or some other bird hawked it up, bits it couldn't digest. Makes a change from the takeaway chicken bones they usually drop.