Possible yellowhammer attacked by magpie

We have had a little baby bird coming into our garden for about 2 weeks now. 
I’d never seen mum until today. 

Today I was looking out the kitchen window and noticed a magpie in the garden, and in the spot where this baby bird usually spends most the day - and then I noticed it was attacking the baby bird. 

I ran out and the magpie flew off. The baby tried to flap it wings but couldn’t fly and hid under a bush. 

I decided to leave it for a little bit as it was safe under the bush and I didn’t want to stress it out any more. A minute later a beautiful yellow bird came down and I realised it was mum as she was trying to care for it. 

I think its leg is broken  and it can’t fly. A little later that magpie came back. I shooed it off again and the baby bird went and hid inside a large hydrangea bush. 

If it is still alive in the morning, is there anything at all I can do to help it? I’ve grown quite attached to this little baby bird and I’ve never seen a bird like its mum before, looking it up I do think it appears to be a yellowhammer - not common around here I don’t think. 

if anyone has any advice I’d really appreciate it. 

  1. Thank you
  • Most bird species, esp garden bird species, both sexes feed their young. I can't comment much on the i.d. other than 'beautiful yellow bird' is more likely a male (unless we're talking blue tit and great tit when it's either). 

    As with someone a week or so ago posting about a young bullfinch, I reckon this is still too early for a young yellowhammer.......not withstanding exceptions and climate change etc.

    Re the events, it's hard, but always best to leave nature to take its course. Exceptions being pets where intervention makes sense, ideally before any attack happens. Magpies, woodpeckers etc are all intelligent and will come back to known food locations. The victim, very often, is beyond saving, so would end up a lost food source and go to waste.