This is a male Indigo Bunting, Passerina cyanea. Once upon a time, it belonged in the family Fringillidae, but that has changed due to genetic data which has allowed this bird to be reclassified in to a new family, Cardinalidae, with its closer kin: the gross-beaks, cardinals, tanagers, and other buntings.
That said, I really like this species because of its powder blue feathers trimmed with black. I was stunned the first time I saw this species, as you might imagine.
The second image shows this little fella belting out his love song. You have to admire these colorful sparrow-sized birds all dressed up in electric blue and singing like rock-stars to anyone in the vicinity. I became an instant fan. On one of my last trips to the Fort Worth Nature Center and Reserve before moving to west Texas, I was treated to a farewell concert by one of these guys. I’m still a fan.