take food away from them till 5or6 then feed them so as they know is you that gives them food shake a tin with some food in it so as the birds hear it rattle it will make it easier to get them in . the birds will soon fly up to board to have a look around wait till you see them doing this before you let them out. when you let them out make sure the birds are hungry and after a short while shake the tin the birds will soon relate this sound with food.