Nice bird - most of the time, (now) I much prefer 2 x 3 - landscape as I think the when the bid is longer than wider, (if you see what I mean), it is more pleasing as somehow portrait makes the main part of the image look smaller when the aforementioned is the case. - portrait works when you have an "upright" bird
So I would also go for a landscape and keep the background as OOF as possible, providing you can get the composition correct.
I think Joe's crop maybe too tight for some on here!
Mike "the experts" may be able to do a little more with PP