Yellow bill could indicate either a Great Egret or a Cattle Egret.
However, if it's as big as you think, that rules out the Cattle Egret.
Also counting against the C. Egret is the location. They are almost always found away from water.
I'm voting for Great Egret.
not to argue Ralph, but when I lived in Ontario, we used to see alot of Cattle Egrets hanging out down near Point Pelee, Rondeau Prov Park, and Long Point Prov Park. They were in the fresh water marshes.
LOL I did say "almost".
Without doubt they will avail themselves of the surrounding resources but they do show a strong preference for fields, pastures and such like habitat, more so than our other large waders.
They bear the "Cattle" epithet for a reason.
You make a good point though, Paul. With Nature there are few absolutes.
I've actually seen one sitting on top of a cow and you just never know what you will see, today I came across a GB Heron and a Bald Eagle sitting beside each other in an Oak Tree....
Most animals appear larger than the tape measure or scales say.
Also, the length quoted is bill tip to tail tip. The wader's long legs and upright stance can skew our perception of size.
Regardless of the details, it's an elegant sighting.