Good idea, I will try to describe what I have done.
I have done a lot of things at once, but focusing on different aspects of flying outside.
First of all I did a lot of recall training in my home. I combined it with building up strength in her flight muscles and ligaments by training longer flights in an indoor arena. I also had her get used to sounds, lights and movements of the outdoors by taking her for a lot of walks in a harness.
Once recall was working 100% I moved some of my training outdoors in a harness and a long line. The thing is, once you are outside, there are a lot of other factors, the bird needs to look past and just focus on you. To highten my success rate, I started by placing her on grass, then stepping a few metres away and called for her. Ususally they will really want to come to you, as sitting outside and sitting low is a little scary. Once this works, I would place her at shoulder level and call for her. Eventually I would place her higher than me and call her. All this was done with no more than 2 metre line. You will also see, the higher you place your bird, the longer they take to get back to you, as you are not their instincts favorite place anymore. You with your training are teaching your bird to ignore their instincts but come, when called.
I also took her out on quite windy days with a 15m line on. I would then ask her to fly and come back to me right away. The wind would take her the first few times. The reason for this is to teach the bird to navigate in windy conditions, as wind will carry them quite far in seconds, if they have no clue how to counteract the wind in their flight. Once your bird either fly back to you or choose/is able to fly to the ground, you are now ready for small recalls without harness.
Once you are at this point, you start from scratch again from the first time you went outside with a harness. Start with small 2 m recalls from lower places. Once that works every time, you can place the bird at shoulder level and slowly move further and further away. Once this works, you can start placing the bird above shoulder level. Remember if you use trees, if the bird is having a good time in the trees, to let the bird come back to the tree and enjoy themselves after a recall. If they think recall means no more playtime, they will stop coming.
At this point Trudi is doing small recalls from 3-5m trees with little intervals, where she can break some branches etc.
Going forward I will train in progressively taller trees and windier conditions only moving at one of the factors at a time (either taller trees or windy conditions).
If anyone wishes to do free flight, you have to expect about 6 months of training before you can move outside with no harness on (depending on how often you train and how fast your parrot learns)
