DAWN CHORUS

Juliet: Wilt thou be gone? It is not yet near day: It was the nightingale, and not the lark, That pierced the fearful hollow of thine ear; Nightly she sings on yon pomegranate-tree; Believe me, love, it was the nightingale.

Romeo: It was the lark, the herald of the morn, No nightingale: look, love, what envious streaks, do lace the severing clouds in yonder east; Night’s candles are burnt out… - William Shakespeare.

Nearly wherever we might travel we will be rewarded with singing birds. Bird song is a series of notes that are repeated in more or less the same sequence. It is generally under the control of male hormones and is concerned with the breeding cycle. For many birds, song has little to do with joy and a lot to do with aggressiveness - in short, song is a substitute for territory defense. Over 900 variation shave been recorded for the Song Sparrow song but it is sufficiently similar to pack the same message to any nearby Song Sparrow - this patch is mine!

Birds sing most vigorously in spring and males without mates are the most vigorous singers. Once the activities of raising a family get under way, singing by males begins to wane. In British Columbia, singing is at its peak in May and June. Following the breeding season many birds begin to molt feathers and they fall silent at this time.

Dawn is when most birds sing the loudest and most often. Singing tapers off through the day until evening when it begins once more. Wrens and vireos are exceptions singing throughout the day, and the Swainson’s Thrush and Hermit Thrush do some of their best singing in the evening. In April, singing begins about the time of sun rise but by June, birds launch their singing as much as an hour before sun up. First up is the American Robin and Song Sparrow in very dim light followed by other species as the sun begins to rise. Light levels also stimulate singing in nocturnal birds such as owls and night hawks, but in the reverse to daytime birds. A natural experiment happened many years ago when an eclipse of the sun stopped diurnal birds from singing and coaxed nocturnal birds to open up (Ehrstrom, Bird-Banding 27:193-4 (1956)).

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