Good job Holly, as it stands I don't see how you could have taken a better shot.
Birds are amongst the most uncooperative subjects there are, particularly when they're perched in trees... and when they're re-enacting the battle of brittain over John's back yard

The only way to improve on what you've done is to beg, borrow or steal the telephoto lens you mentioned elsewhere
The texture of the feathers of birds that aren't brightly coloured look pretty amazing if you can get close enough AND get a clear shot which is no mean feat but well worth the effort.
After
many failed attempts I got a decent shot of a Rainbow Lorikeet a while back more by good luck than good management -
http://www.jwjonline.net/JWJforum/index.php?topic=1027.msg21899#msg21899