The first striped bass of the year in Maine should be showing up in the next couple of weeks. Typically the smaller ones will be in large schools and found in the tidal rivers and estuaries. The only place I've been able to consistently find the larger stripers this time of year is around the runs of river herring. This could be at the base of dams that block the spawning runs or the mouths of small creeks that empty on to a beach or some structure in a large river that provides a current break....all places that concentrate the herring.
In shallow water my favorite fly is a large, white, deerhair headed fly. It has the size, bulk and action to imitate a river herring and occasionally trigger the big stripers to bite. Normally I like to tie them with a fish shaped head and I don't have any complaints about how they work but I decided to tie one up with a subbug style head. I figure if I can get a little more side to side action and wobble to the fly it will work better even if it doesn't exactly have the shape of the fish's head. The first two pics are how I normally tie these flies.
These pics show the ones I tied with the subbug style head.
I also tied up some more muskie/pike flies. I tied up some big deer hair poppers which are basically the Afton Angler's hang times with deer hair heads. He's got a bunch of flies up on his facebook page that I could stare at for hours....pretty amazing stuff.