From what others have told me, when you first take a bird outside, be very very careful not to overwork them. I was told 4-5 flights only. I didn't start increasing distance for my A to B flights till about 5th flight outdoors. First day they are usually very very cautious, and its easy for them to miss a landing which can result in them being scared to fly in future. Its really important to make it a positive experience for them.