February 1947 – vol. 40, issue 2–43 ALTHOUGH a great deal has been written on the subject of bird song, relatively little is known about seasonal and daily fluctuations in song output. Alexander's [i, 2] work accounts for a very large number of species and gives the dates between which birds will usually be in full song, irregular song and sub-song, but no indication is: given of the variations during the period of full song. The bi... This article is only available to registered users.To read more, please log in or purchase a subscription.