During our recent visit to southern US, we saw quite a few great blue herons, as ubiquitous as are grey herons in the UK.
These American birds are among the largest herons, being twice as large as a great egret, and larger than the European grey heron.
Note the blue dominance of the beak, compared to the yellow in that of the great blue.
Apparently, the little blue is white during its first year. Maybe there were more around than I thought!