Update: Slow..... but steady progress.
The day before the haze, as Birdie was outside in it's cage, a few ioras (an adult and two smaller ones) were seen perched withing a foot and 'talking' to little Birdie. Other types of common garden birds were also seen near the cage. Mayb checking birdie out.
My 'plan' is materializing! My guess was correct. There are Ioras out there that may/can befriend and take Birdie and 'de-domesticate' it. Seeing this development, *I told Kakak to immediately open the cage door the moment she sees the Ioras again.* edit.
The next day, maybe becoz Kakak misunderstood me, she left the door open the moment she hung the cage, and didn't wait for the wild Ioras. What happened later was quite funny, I think. A bigger, brown garden bird went in the cage and perched beside Birdie. Could it be the food inside? Or, it wasn't funny at all because that bigger brown bird could have been a predator/carnivore and ate Birdie!
The past few days Birdie was kept indoors - it was 'no attempt' days caused by the haze.
Since it rained yesterday evening and the sky has cleared considerably, today Project Freedom continues!
Cage was left open upon hanging at the usual outdoor place, again. Later, Birdie's wild friends came. Then Birdie came out of the cage by itself and flew away with them. But...... came back 3 hours later visibly tired, hunched over as it perched. It was observed 'hanging out' (with it's newfoud 'gang') in the vicinity hopping, perching, flying in and out of trees within a radius of about 10metres from its cage. She has since been taken in and recuperating. Very famished too.
Will continue again tomorrow and told Kakak to leave the cage as in the same place and keep fruits and mealworms fresh daily for the next 2 weeks. Hopefully it will be able to hunt its own food and dependency on 'home food' will diminish.
Might just turn out to be like your sparrow. Half -jinak, and comes by regularly for snacks