Egg dates.—Arizona: 14 records, May 23 to July 1; 7 records, June 2 to 18, indicating the height of the season.
DENDROICA PETECHIA AESTIVA (Gmelin)
EASTERN YELLOW WARBLER
Plates 24, 25
HABITS
The familiar yellow warbler, also commonly called the summer yellow bird or wild canary, is the best known and the most widely known of all of our wood warblers. It is one of the few birds that almost everybody knows by one of the above names. It is universally beloved as it comes to us in the flush of budding spring, gleaming in the shrubbery, like a rich yellow flame among the freshly opening leaves, or bringing to the apple orchards a flash of brilliant sunshine to mingle with the fragrant blossoms. As Dr. Chapman (1907) says: “In his plumes dwells the gold of the sun, in his voice its brightness and good cheer. We have not to seek him in the depths of the forest, the haunt of nearly all his congeners, he comes to us and makes his home near ours.”
The yellow warbler, as a species, is also the most widely distributed member of its family. Its breeding range extends from the Atlantic to the Pacific in both Canada and the United States (110 degrees of longitude), and from the Barren Grounds in northern Canada to Mexico and the Gulf States (40 degrees of latitude). Its winter range covers 54 degrees of longitude and 31 degrees of latitude in Central and South America. Professor Cooke (1904) says: “The extreme points of the yellow warbler’s range—northern Alaska and western Perú—are farther separated than the extremes of the range of the black-polled warbler, which is considered the greatest migrant of the family.” But it must be remembered that the yellow warbler breeds much farther south than the black-poll.
Spring.—The spring migration of the yellow warbler is long and partially circuitous; eastern yellow warblers that winter as far east as British Guiana probably make a roundabout flight to Central America, as there seem to be no springtime records for this bird in the West Indies and few for it in Florida. These birds may fly across the Gulf from Yucatán to Cuba and Florida, but the main flight is probably directly north from Yucatán to Louisiana and other points on the Gulf coast; they have been repeatedly seen flying northward in the middle of the Gulf. There is also a considerable migration along the coast of Texas, which I have personally observed.
The migration is also prolonged or very irregular, for according to the dates of departure given to me by Alexander F. Skutch (see under Winter), the last of these warblers do not leave Central America until the very last of April, or the first of May, after the first arrivals have reached New England; some of these records, however, may apply to one of the western races. After the birds reach the United States, the migration fans out northward and northeastward and seems to be more rapid. Of this Frederick C. Lincoln (1939) says: “Coming north from the Tropics these birds reach New Orleans about April 5, when the average temperature is 65° F. Travelling on northward much faster than does the season, they reach their breeding grounds in Manitoba the latter part of May, when the average temperature is only 47°. Encountering progressively colder weather over their entire route, they cross a strip of country in the 15 days from May 11 to 25 that spring takes 35 days to cross. This ‘catching up’ with spring is characteristic of species that winter south of the United States and of most of the northern species that winter in the Gulf States.”