Very nice photo of a male Anna's Hummingbird. It's not Costa's, which is smaller, has a slightly shorter and noticeably more curved bill, and a distinctive unusually long gorget which actually extends all the way onto the green on the bird's side. In Anna's, the tail extends well behind the wingtips as in your bird, whereas in Costa's it does not. The white around Costa's eye is isolated by a small bridge of color extending from the nape to the gorget giving the bird a "masked" appearance, whereas in Anna's a bridge of lighter color extends from the eye downward and rearward. Here's a photo of Costa's for comparison. Note especially the characteristic gorget shape.
