Not common at my locale. Not at all. That's why I found it surprising when I saw them in San Diego. Now I know how highly variable they can be, depending on their environment and other factors. For whatever reason, that locale in San Diego favored metallics and it was all or most of their bodies! Darn about the blue.

@ guido: I do have video somewhere, of the frogs eating. As soon as I find it, I'll post on youtube and share the link. I can't find a picture but the housing was plastic and converted (drilled holes in top, and sealed the bottom) from packaging that this toy came in: Doozy Fun Marionette : 40050852A523499A474 - Buy.com