Dr. Bryant, in his visit to the Bahamas, was eye-witness to the migrations northward of these birds, as they passed through those islands. He first noted them on the 6th of May, towards sunset. A number of flocks—he counted nine—were flying to the westward. On the following day the country was filled with these birds, and men and boys turned out in large numbers to shoot them. He examined a quantity of them, and all were males in full plumage. Numerous flocks continued to arrive that day and the following, which was Sunday. On Monday, among those that were shot were many females. On Tuesday but few were to be seen, and on Wednesday they had entirely disappeared.
Near Washington, Dr. Coues observed the Bobolink to be only a spring and autumnal visitant, from May 1st to the 15th distributed abundantly about orchards and meadows, generally in flocks. In autumn they frequented in immense flocks the tracts of _Zizania aquatica_, along the Potomac, from August 20 to October.
The Bobolink invariably builds its nest upon the ground, usually in a meadow, and conceals it so well among the standing grass that it is very difficult of discovery until the grass is cut. The female is very wary in leaving or in returning to her nest, always alighting upon the ground, or rising from it, at a distance from her nest. The male bird, too, if the nest is approached, seeks to decoy off the intruder by his anxiety over a spot remote from the object of his solicitude. The nest is of the simplest description, made usually of a few flexible stems of grasses carefully interwoven into a shallow and compact nest. The eggs, five or six in number, have a dull white ground, in some tinged with a light drab, in others with olive. They are generally spotted and blotched over the entire egg with a rufous-brown, intermingled with lavender. They are pointed at one end, and measure .90 by .70 of an inch. They have but one brood in a season.
In some eggs, especially those found in more northern localities, the ground-color is drab, with a strong tinge of purple. Over this is diffused a series of obscure lavender-color, and then overlying these are larger and bolder blotches of wine-colored brown. In a few eggs long and irregular lines of dark purple, so deep as to be undistinguishable from black, are added. These eggs are quite pointed at one end.