BIRDS OF THE UNITED STATES. 
109 
and with a small downward tendency, so as to cause a central depression. 
Sometimes the first pieces are perfectly level for the space of an inch or 
more, and the necessary inclination is given to the topmost layers, which 
are made to dip towards the centre of the nest. Basally, the structure is 
four inches wide, but gradually increases to four and a half at the top. 
The height is two and a half inches, and the depth of the cavity often 
less than a half inch, and so shallow that the superior surfaces of the 
eggs actually extended above the level of the outside margin. So super- 
ficial is the cavity, in some cases, that the eggs and young are often 
jostled upon the ground when the wind blows with more than ordinary 
velocity. To obviate this difficulty, as much as possible, a tree is often 
chosen on the southern aspect of a hill, or in a place carefully ]n’otected 
by natural or artificial defences. From the elevated nest the ground- 
structure differs immaterially. This difference is to be observed not in 
size, nor in the manner of construction, but in composition. All nests 
which we have seen from places both east and west of our great cen- 
tral mountain system, have the ground-work of grass-stems, stubble, etc., 
loosely arranged, and are lined with fine culms and leaves of soft grasses. 
In the Plate the nest is considerably reduced, placed in the background, 
and on a branch of a species of pine. The female is also diminished, and 
represented as engaged in the duties of incubation ; whereas the male, 
owing to his beauty of form and plumage, is given special prominence, 
and appears three-fourths of his natural dimensions. 
In the Gulf States, Louisiana especially, according to Mr. Audubon, 
nesting generally begins in April, and sometimes as early as March. In 
Pennsylvania, frequently as early as the fifteenth of the former month, 
excejDt in seasons which are unusually backward, when this important 
business is delayed until May. The fifteenth of this month marks the 
time in New England. In Illinois, and other Western States, it begins in 
early April, while along the Pacific coast, the period ranges from the first 
to the twentieth of May. Two broods are annually raised in most local- 
ities. The second does not, it seems, appear at any regular time, but may 
