Another shot of the bird which I think looks like a young female blackbird - with a strange head!! You can see its poor foot in this shot. He chases the robin off of the mealworms!!
Well this explains it then. You are in England and I am in America the birds a totally different here than they are there. I don't have any books on European Birds so I really can't answer your question. Hopefully someone from your side of the pond will see this and answer it for you. Especially after this wonderful capture that you've done.
@joansmor Just checked it out as I have never heard of this bird in the UK but it seems there have been sightings. When you look closely at the beak I don't think it's a cowbird. I am still thinking a UK blackbird - maybe the head has moulted and it is yet to grow it's adult feathers? Thanks for looking!!
@pamknowler Admittedly by sister @janiskay is much better than me at this. But when I want to find something I just type in the search bar what I think is close. Tree with purple flower, European black bird and then usually click on pictures. Amazing what you can find. But I did forget to check the beak. Probably needed more coffee.
What do you think?