Playing statues

With this hot weather that we are having I like to sit outside the back door in the shade in the afternoon where I listen to the play on the radio and watch the birds, butterflies and bees and look at the flowers.
As there isn't really a lot of room, I find it best if I place the chair just to the right of the door as this is the best place to be able to hear the radio without bringing it outside and I also get a good view of the garden without moving my head too much.
The main reason I don't want to move is that I would like the birds to get used to me being there. They do come over but are very, very cautious so this week, I have been paying particular attention to their behaviour.
The hedge sparrow doesn't bother about me at all because she is pottering about under the plants finding insects and only appears briefly from time to time and even then she doesn't seem to be too worried despite the fact that they are very shy birds.
The house sparrows however, exhibit totally different behaviours. They will come and sit on the fence behind me and I know they are there because I can hear their feet scratching on the wire. Some will even come onto the bird table which is about three feet behind my head but only if they can't see my face and eyes. So I sit very still and probably all they can see of me is the top of my head.
The ones that get on the seed feeder, which is about five feet in front of me, also don't seem to worry if I keep my eyes looking down but the strangest thing of all is that if I am bent over (as I did this afternoon while I did some 'dead heading') none of them bother about me even if I am moving about. I think they feel happier if I don't resemble a human shape in the upright position!