Nice shots - you've managed go get a little background in a couple of them, so it's not just "bird on blue"! A could of them feel a tad over-exposed though? I remember reading about shooting stuff against bright blue sky, and the suggestion was to under expose by about .7 I believe...
Funnily enough, I had a bit of a schoolboy error on this trip. I got out both cameras before I went. I was going to take the 5D MkII as I generally use this for most non-sports stuff, so I changed it from jpg to RAW (I was using both cameras last week for sports).
I got my gear together & at the last minute decided to take the 1D MkIV instead, but forgot to change it to RAW. So I don't have the same latitude to adjust.
I found it quite difficult to expose for these birds because they have black heads (well very dark brown) & white bodies & the sun was high in the sky with no cloud.
In the full size shots you can still see the individual feathers in the tail in shot 4 which is the one that looks most overexposed.
They were actually shot with + 1/3 or 2/3 stop to keep the whites bright & detail in the head & beak.
Out of interest, here are the histograms for 1,2 & 4 in order:
and here's a crop of an unprocessed section of 4
black head against white body in bright sun = nightmare!