Chronometric Observations of the Song of Fringilla cœlebs Linn.

Abstract

DURING the 1946 breeding season of the common chaffinch (Fringilla cœlebs L.), 5,468 observations were obtained of the song interval, that is, the time taken by the cock bird to utter his characteristic sequence of notes¹. A split-second hand chronometer was used to record the duration of the interval to the nearest tenth of one second, and a correction was applied to eliminate the personal equation of the observer. Corrected times are considered accurate to ± 0.1 sec. No particular care was taken to ensure that successive records were obtained from the same birds, since it was desired to examine a typically representative cross-section of the local chaffinch population. Recording was made under a variety of weather conditions to assess the possible influence of certain meteorological factors on the duration and frequency distribution of the interval value defined previously.