Believed to be a hybrid Lesser-black backed Gull x Herring Gull due to large mirrors visible in wings, lack of bold red eye ring and no bleeding of red spot on upper mandible.
I thought maybe a chiffchaff (autumn juvenile male as quite bright lemon yellow) or if not a willow or wood warbler? Found close to Battersea Park. Sadly victim to a window collision.
Unsure if is a short toed treecreeper or not
It is the calling/singing bird in the foreground that I am interested in, starting at about 00:02 and again 00:10 in the recording. I only saw the bird fleetingly as it flew away. Significantly smaller than a blackbird. Was perched in large bush near river.