Dead Grass, Yellow Bird

The swamp across the road from the train station in Kingston; I have no idea what those reeds or marsh grass are, but they appear to get approximately twelve feet tall.
Almost certainly a yellow warbler, since there are other pictures and I can get a look at its head and thus convince myself. (Though in the case of yellow warblers, a less shiny shot might be diagnostic with only the provided view.)
This is with a zoom lens at the full 300mm extension. I want a hand-holdable 600mm f3, dammit, however impractical the desire. (Well, OK, if some combination of diamond optics, that metal sheet with nano hole fresnel lens/diffraction grating approach being proposed for space telescopes, and scandium lens tubes become collectively available, along with a willingness to abandon the pure-refractor habits of lens designers, to make the thing short enough, it's just possible I could have such a thing. But not soon, alas.)