If you get a chance to travel to South Texas (or Texico as they nickname it there), then you certainly should. I had no idea that it was one of the top birding locations in North America. I would HIGHLY recommend it.
I spent 5 days there with a Canon 500mm f/4 (which I rented from lensrentals.com) + a 1.4x extender (that's me with the big gun below).
Here are my favourite 23 images (from about 1000!).
http://www.samchadwickphoto.com/expedition-texas.html
Enjoy.
Sam

