Blackbird Struggling - How can I help?


I have a blackbird nest in my garden, the first brood of 3 all fledged successfully, as far as I know. There is now another single chick and mother (father was killed by sparrowhawk) and mother had been collecting food and taking it to the chick in the nest. The chick has now been out of the nest for 4 days (today being day 5). It started off in the hedge with mother returning to it and feeding it and it got back to the nest at the end of day 2, exhausted (as was poor mum). I assumed all was well as the chick had returned to the nest but still kept my cat in during daylight hours to give them peace whilst the chick gets the hang of flying. I let the cat out in the early hours of Saturday morning and he brought the chick in, he's not much of a hunter so I have assumed it was on the ground. He let it go and whilst the cat was shut elsewhere I managed to catch the chick quickly, calmly and quietly in the dark in a box and released it close to the nest in the hedge but it fell to the ground so I left it the as I didn't want to interfere anymore. There was no evidence of any blood in the box so I hoped that it hadn't been injured physically.

Yesterday morning I went out and it wasn't where I had left it which I took as good news and again kept the cat in all day. Mother blackbird was still feeding baby yesterday and it was managing to fly a few inches off the ground into the hedge however it doesn't appear to have made it back to the nest.

This morning the baby is again on the ground in the corner of my garden where the fence meets the house and mother is around and although I have seen her feeding herself I haven't seen her feed the chick (that's not to say that she hasn't). I have put a handful of mealworm about 2 feet away from the chick in the hope that mother will come and feed it. It is alive but it doesn't look great. Is there anymore I can do to help or should I just keep away and hope for a happy ending?

I also wondered if they have abandoned the nest after the father's demise? He wasn't taken from the nest but elsewhere in the garden and the nest is well concealed in a shady corner. Would them abandoning the nest be likely?

Any advice or information would be greatly appreciated. I have become emotionally involved in their struggle for survival and am keen to do whatever I can to help but don't want to make matters any worse with my efforts of kindness.

Many thanks in anticipation.