This video from the USA says about itself:
Black-throated green warblers are a very common breeding species in Maine. They can be found in a variety of habitat but prefer mixed deciduous forests. Their buzzy song is often one of the first warbler songs I hear in the spring. © 2012 Garth McElroy.
From the Cornell Lab of Ornithology in the USA:
The Changing Cast of Maine‘s Famous Spruce-Woods Warblers
The magical songs of warblers have echoed through the Maine woods for millennia. In the 1950s, noted ecologist Robert MacArthur made these warblers famous by studying how different species can live together by using different foraging areas within the same tree. Now, 60 years later, a researcher revisits the spot to see what has changed and what has stayed the same. Read the story and listen to the calls.
BE RIGHT BACK, ROAD-TRIPPING TO THE NEW NATIONAL PARK The tens of thousands of acres of Maine forest previously owned by one of the co-founders of Burt’s Bees are now federally protected — just in time for the 100-year celebration of the National Park Service today. [Hilary Hanson, HuffPost]