INDIGO BIRD. 
263 
mences again as before. Some of our birds sing only in spring, 
and then chiefly in the morning, being comparatively mute du- 
ring the heat of noon; but the Indigo bird chants with as much 
animation under the meridian sun, in the month of July, as in 
the month of May; and continues his song, occasionally, to the 
middle or end of August. His usual note, when alarmed by an 
approach to his nest, is a sharp cA^/), like that of striking two 
hard pebbles smartly together. 
Notwithstanding the beauty of his plumage, the vivacity with 
which he sings, and the ease with which he can be reared and 
kept, the Indigo bird is seldom seen domesticated. The few I 
have met with were taken in trap-cages; and such of any species 
rarely sing equal to those which have been reared by hand from 
the nest. There is one singularity which, as it cannot be well 
represented in the figure, may be mentioned here, viz. that in 
some certain lights his plumage appears of a rich sky-blue, and 
in others of a vivid verdigrise green; so that the same bird, in 
passing from one place to another before your eyes, seems to 
undergo a total change of colour. When the angle of incidence 
of the rays of light, reflected from his plumage, is acute, the 
colour is green, when obtuse, blue. Such I think I have ob- 
served to be uniformly the case, without being optician enough 
to explain why it is so. From this, however, must be excepted 
the colour of the head, which being of a very deep blue, is not 
affected by a change of position. 
The nest of this bird is usually built in a low bush, among 
rank grass, grain or clover; suspended by two twigs, one pass- 
ing up each side; and is composed outwardly of flax, and lined 
with fine dry grass. I have also known it to build in the hollow 
of an apple tree. The eggs, generally five, are blue, with a blotch 
of purple at the great end. 
The Indigo bird is five inches long, and seven inches in ex- 
tent; the whole body is of a rich sky-blue, deepening on the head 
to an ultramarine, with a tinge of purple; the blue on the body, 
tail, and wings, varies in particular lights to a light green, or 
verdigrise colour, similar to that on the breast of a peacock;. 
