Birders come from long distances to Niagara Falls State Park to watch and find various Gulls along the Niagara River. This year they have been coming because at least two uncommon gulls were present. I myself, cannot tell one from another.
There is often minor differences between what is common and what is not, and are only traits an experienced birder can differentiate.
What I like about the gulls is the action on the river. They squawk, fight, steal, mob, and almost drown each other when a fish is caught. It is not unlike eagles in that respect. In the end, there is always a victor.