In their migrations through Massachusetts these Warblers are everywhere quite abundant in the spring, but in their return in autumn are not observed in the eastern part of the State, though very common in the western from September into November, remaining long after all the other Warblers are gone. None remain during the summer.
In Western Maine, Mr. Verrill states, it is quite common both in spring and in fall, arriving in April, earlier than any other Warbler, and again becoming abundant the last of September.
I found it plentiful in the vicinity of Halifax, where it occurs throughout the summer from May to September.
Mr. Ridgway gives this species as perhaps the most numerous of the transient visitants, in spring and fall, in Southern Illinois. It is very terrestrial in its habits, keeping much on the ground, in orchards and open places, and its movements are said to be wonderfully like those of Anthus ludovicianus.
In the vibratory motions of its tail, especially when upon the ground, these birds greatly resemble the Wagtails of Europe. They have no other song than a few simple and feeble notes, so thin and weak that they might almost be mistaken for the sounds made by the common grasshopper.
The Red-Poll usually selects for the site of its nest the edge of a swampy thicket, more or less open, placing it invariably upon the ground. This is usually not large, about three and a half inches in diameter and two and a half in depth, the diameter and depth of the cavity each averaging only half an inch less. The walls are compactly and elaborately constructed of an interweaving of various fine materials, chiefly fine dry grasses, slender strips of bark, stems of the smaller plants, hypnum, and other mosses. Within, the nest is warmly and softly lined with down and feathers.
Mr. Kennicott met with a nest of this bird at Fort Resolution, June 18. It was on the ground, on a hummock, at the foot of a small spruce, in a swamp. When found, it contained five young birds.
Their eggs are of a rounded-oval shape, and measure .70 of an inch in length by .55 in breadth. Their ground-color is a yellowish or creamy-white, and their blotches, chiefly about the larger end, are a blending of purple, lilac, and reddish-brown.
PRAIRIE WARBLER.