I live in East Texas around the Lufkin/Nacogdoches area and have a couple of birds that keep catching my eye. The first one that showed up is a solid green color, kind of dark. It never sticks around for long so I can't get a close up look or any clear pictures of it.
It is about the same size as a cardinal, only sleeker with a smooth slender head and has a cone shaped beak. I have seen it a couple of times drop out of a tree onto the ground for a few seconds at a time, then back into the trees or around the house. It seems very skittish, but likes our birdbath. It tries to get to the birdfeeder, but the cardinals and blue jays chase it off.
A few days after first spotting this green bird, I noticed another that usually shows up following it around. This one looks the exact same only it is a very bright solid red color. I would have thought the red one might have been a young cardinal or something like that, but the green one has kept me guessing since I can't find them on your site.
Some of my descriptions (except for color) may be a little off since, like I said, they don't sit still long and it is hard to get a good look, but I will keep trying for a picture if it will help.