Gasson, P, Buxton, E. J. M, Dewar, J. M, Dewar, J. M & Buxton, E. J. M / September 1939 – vol. 33, issue 4–118 SIRS,--In "Some Notes on t h e Diurnal Song of Birds " (antea, p . 4) Mr. Marples states t h a t on t h e average t h e Blackbird, a t Inverness, begins t o sing in the morning 74 minutes earlier than Blackbirds do i n Hampshire, t h a t is, after correction for effect of difference of latitude on time of sunrise. Since twilight lasts longer in the north t h a n in t h e south, it is t o be expected... This article is only available to registered users.To read more, please log in or purchase a subscription.