This bird was tough to snap a picture of. It seemed to be ADHD. It moved quickly from tree to tree and branch to branch. I believe it is a Ruby-Crowned Kinglet. If I am wrong let me know.

Ruby Crowned Kinglets are said to be hyperactive, which definitely fits this bird. This type of kinglet is said to have an uneven eye ring, which this one does. The Ruby-Crowned Kinglet is said to have brighter greenish edges on the wing and tail feathers, which you can see here.

This bird was in a wooded area right next to the Hudson River in an area with different kinds of birds.

According to Merlin, the ruby crown is only on the males and is usually hidden. If it becomes agitated you might see it.
This bird was interesting to observe. The Hudson Valley in Southern NY is actually in its non-breeding range. What birds have you caught during this migration?