The First Morning Song of Some Birds of Washington, D. C.; Its Relation to Light

摘要: My interest in the singing behavior of birds began earliest childhood. This has become intensified as a result work W. Garner and myself dealing with effects length day upon growth reproduction plants. The present paper is intended to be more or less supplementary an earlier historical contribution (1928) opinions theories bird migration from point view light changes seasonal day. Since it obvious that various rhythms night govern many common plant animal one way another, evident every phase should expected closely synchronized these influences. not least among these. first morning song been given attention by number field naturalists. To most casual observer, awaken very early since their begins long before actual sunrise. So well this appreciated country people are greatly disturbed sleep dawn medley dozens vociferous birds. It would appear function some daybreak. easily seen warm season advances spring equinox toward summer solstice sunrise becoming progressively each day, advanced keep pace phenomenon regular proportionate way.