I photographed this young Painted Bunting on South Padre Island in early May when a lot of neotropical migrants were stopping over so I couldn't keep up with them all. 
I believe this is an immature male as in addition to the greenish upperparts there is almost reddish feathering on it's underparts.
Like a number of songbirds it waited for other birds, especially big ole grackles, to get out of the water before it entered.  It finally go in but it was in a location that I couldn't get pics.SeEtta