Portal de Periódicos da CAPES

Routes of Bird Migration

1905; Oxford University Press; Volume: 22; Issue: 1 Linguagem: Inglês

10.2307/4069869

1938-4254

Wells W. Cooke,

Mediterranean and Iberian flora and fauna

THROUGHOUT the broad expanse of level land between the Allegheny and the Rocky Mountains, bird migration is so uniform that a species is expected always to appear first at the more southern localities.An apparent exception to this rule is noted in the case of several species whose recorded dates of spring arrival in northern Texas are earlier than the corresponding dates many miles to the southward.Thus the first Black and White Warblers (M/ncoti/ta varia) were seen near Corpus Christi March 21 (average of five years), near San Antonio.March 15 (average of seven years), and in northeastern Texas March 13 (average of four years).The distance from Corpus Christi to latitude 33° in northern Texas is 350 miles, a distance that ordinarily is passed over by the Black and White Warbler in about 17 days, since its average rate of travel in the Mississippi Valley is not far from 20 miles per day.This species therefore arrives in northern Texas some three weeks earlier than would be expected from the records of its spring appearance in southern Texas.The records for ten years give March 21 as the average date of arrival of the Parula Warbler (Compsothlypis americana) at San Antonio, while the corresponding date 300 miles farther north is March rq.