You don't say how long you've been shooting, particularly how long you've been shooting birds. They are not an easy thing to do well and these are quite nice.
That said, my C&C would be as follows:
1. Good exposure and good focus on the birds. Bonus points for getting both birds in decent focus. The branches in the background really distract from what might otherwise be a stellar image. I know ALL too well that it is not always possible to choose a better background with birds, but my advice would be to *always* be mindful of the setting and thinking about how you could minimize background distractions. For instance, in this photo, perhaps you could have knelt or otherwise shot from a bit lower perspective, just enough so that the birds would have ended up against the blue sky instead of the branches. Or, possibly by moving back just a tad, or to the right a bit, you could have gotten them "framed" in that triangle of blue sky below the branches, photo left.
Again, not always possible. But I've found that the more aware I become of my backgrounds, the more often I find that I *can* control it better than you'd think!
2. Very nice, other than the centered heron which was already mentioned. As someone else said, *don't* use rule of thirds as a hard-and-fast rule, but as a guideline. There ARE times when centering works best for the photo--but I'd say if you're in doubt, trying putting it on a third line. In this case, you'd want the GBH on the right-side "third" line, since it is looking toward the left. A general guideline is to give the bird "room" in the picture in whichever direction it is pointing.
3. Again, nice shot. It feels slightly tilted to me, but that could just be because of the angle the bird is flying at, the branch going crossways on the right, etc. Speaking of which, I'd be tempted to crop that big branch right out of there. Put the Egret on the right third line, right at the intersection of the top lines (if that makes sense--in other words, towards the upper right of the photo). Also, I'd say watch your highlights--white birds are especially hard to shoot in bright sunlight. You've just about blown out the white highlights on the bird. Since this isn't a close-up shot, I don't know that it matters much but it's something to pay attention to when you're shooting egrets and the like.
Baby Swallows by seastud, on Flickr
Heron by seastud, on Flickr
Great Egret by seastud, on Flickr
Goose heart
