Mystery Black Bird

I live in the Dallas Texas area and I have recently noticed a new bird visiting the bird bath in my back yard every day. I am pretty familiar with the types of birds that come to my bird baths and feeders but am a little puzzled by this one. It looks and sounds just like a starling (shiny solid black with the somewhat multi color sheen that are typical to starling feathers), but it seems much too large to be a starling. It is a little larger than the common male grackles that I am used to seeing here and it is almost as big as a crow. It has been visiting my bird bath daily for about two weeks now, but it always comes alone (no mate and no flock). Anyone know what it might be? I have not taken a picture of it yet, as it will take flight if you try to get too close to it, but I might be able to get one later. Thanks.