One of the prettiest songs you'll hear in the desert of the Southwestern United States and central Mexico is that of the cactus wren, the state bird of Arizona. It's the largest American wren and frequently nests within a cactus plant, including the giant saguaro. It's fun to watch them pop their heads out a massive cactus, not unlike a cuckoo out of its clock.
This particular bird was photographed in Tucson. I wished I'd recorded its beautiful song.