Variation in the Morning Awakening Time of Some Birds in South-Central Michigan

Many authors have commented on the regularity with which birds first sing in the morning, each species apparently having its own particular awakening time. Allard (1930:460), Nice (1943:108), and others have noted that different species followed each other in an orderly sequence of morning awakening song and have referred to this phenomenon as the "bird clock." The first serious study of awakening time was undertaken by Wright (1912, 1913) who recorded awakening times for several years in the mountains of New Hampshire. Allen (1913) published some additions and corrections to Wright's (1913) work and added some of his own records in 1915 and 1922. Allard's (1930) paper listed rising times of 14 species and was the first serious effort in this country to establish the factors that determine awakening times. Also, A!lard's paper was the first published report concerned with the problem of awakening time in which several species of birds were systematically studied during several months of the year. Recently, Leopold and Eynon (1961) published an article dealing with 20 species which also offers a good review of some foreign literature. Other authors have listed their impressions of the awakening times of various species, and many writers have recorded awakening times, particularly for a single species. The most thorough of these latter are the works of Nice (1943) on the Song Sparrow (Melospiza melodia) and Armstrong (1955) on the Winter Wren (Troglodytes troglodytes). Others include Craig (1943) on the Eastern Wood Pewee (Contopus virens), MacQueen (1950) on the Least Flycatcher (Empidonax minimus), McCabe (1951) and King (1955) on the Traill Flycatcher (Empidonax traillii), and Davis (1958) on the Rufous-sided Towhee (Pipilo erythrophthalmus). There are many papers in the literature on the roosting times and flights of several species. The present paper deals only with the awakening time of ten species of birds. Few workers have conducted their studies of awakening time through an entire year and noted the seasonal changes which occur. Allard's (1930) records were gathered from January 15 to September 1, while an unpublished thesis by Walker (MS) was based on records taken from October to July. The works of Nice (1943) and Armstrong (1955) contain records taken at all seasons over a period of several years. Leopold and Eynon (1961) presented data covering the song season only.