Sitta canadensis. Bethel, Maine, Two Canada Nuthatches engage in a vocal duet. 1907 January 19 Canada Nuthatches are common in the Glen Woods just at present, associating with Chickadees (of both species) and with Golden- crested Kinglets. I seldom find more than two of the Nuthatches to- gether, however, They were very noisy this forenoon (10-II.30). Twice I heard two performing what seemed to me an antiphonal duet, one bird uttering the usual nasal whining, the other a kec-kec-kec etc., given rapidly and practically without cessation for minutes at a time and sounding at a distance very like the barking of a Red Squirrel. These kec notes, however, are really softer and more evenly continuous than are the coughing ones of the Squirrel as I had ample opportunity for determining this morning by actual comparison. I watched one of the Nuthatches as it whined almost incessantly for several minutes in re- sponse to the barking of another concealed not far off in dense ever- green foliage. The bird I saw was perched on the topmost spire of a tall living balsam where it sat rather erect, turning its head from side to side, jerking its tail and flirting its wings, with great ani- mation. The duets just described were antiphonal in the sense that one bird invariably used a distinctly different set of notes from those given by the other. Both birds, however, were usually calling at the same time. They seemed very excited and eager. The Chickadees with them showed no unusual excitement. 73