Many of the early field guides (I am looking at the a 1966 Golden Field Guide of Birds of North America just now) mention and show crown patches on kingbirds. I have looked for such a patch through binoculars and spotting scopes since I was a young lad without success! Thus, after extracting the Eastern Kingbird from net A2 on April 30th, I immediately examined the crown. The color was beyond belief. The outer primary tips were also remarkable. The feathers were notched and emarginated. The white terminal tail band, of course, confirms the ID.
While we have not caught another kingbird this season, there are a number of them moving about the station daily. Two were seen chasing an Osprey over the salt marsh just the other day. A single bird was seen on a perch near one of the marsh nets over the weekend. It seems as if they may be nesting in the Park this year.