weaning baby sun conure refusing formula

by Chelsea
(Santa Monica)

My conure is about 13-14 weeks old, has started fledging and used to beg for formula but now never wants to be fed. I don't want to force feed him but I don't want him to starve either. I have offered sunflower seeds, walnuts, bird seed mix, bananas, mashed potatoes, etc. He likes to pick at it but only eats a bite or two and then loses interest. How can I get him to eat without force feeding?