Id like here to say something in defense of experts..
An expert is someone who feels they know something that they wish to share , and has some solid reason to believe what it is.
They too might be wrong.. I stuck my neck out earlier in a post to share what it is I think I can say solidly, that doesn't help me any.
That said, the bird is technically a White egret, The Great White egret term , does get used for it as well.
The Great Blue heron has a white morph, which gets called sometimes Great White heron.
Its said the Great egret and Great blue heron interbreed as well.
So actually any of the terms has an element of doubt , and without blood tests ...
The terms Egret and Heron don't mean anything other than by tradition and decision of naming committees.
but the safer thing is to say nothing , even when I feel I could be of assistance
so Ill stand corrected and do that next time.