280 BACKBONED ANIMALS. 
May, and built by male and female upon the ground, 
generally in communities, being a simple hollow in the 
stubble, lined with horse-hair and grass. 
VALUE.—Game, and as insect-eaters. 
The Crows (Corvide) are birds of large size, and 
possess powerful bills ; the voice is harsh and unmusical. 
The blue jay (Cyanocitta cristata) is the best known of the 
jays, and is widely distributed over America. The nest is 
placed in trees, formed of twigs lined with grass and deli- 
cate fibers, and contains four or five olive-brown, dark- 
spotted eggs. They are migratory in the Northern States, 
Note.—The Canada jay (?. Canadensis) is a guardian bird that 
alights on the moose, hanging from its horns and fur in eager search for 
parasites, an act of friendship the moose does not object to. Other 
species in Europe perform the same office for the reindeer. 
The common crow (Corvus frugivorus) is a familiar form, with a 
purplish-violet plumage, attaining a length of twenty inches. They 
are remarkably intelligent, and form vast rookeries, starting off each 
day and flying for miles, returning at night. They build in trees, the 
nest being composed of twigs and roots, and about two feet across. The 
eggs, from three to six, are laid in April, and are bluish green with olive- 
green or dark streaks. The male feeds his mate during the period of 
incubation, seeds or animal diet being equally to their taste. They 
have been seen to drop clams from a height to break their shells, and 
the rocks about Ocean Point, Maine, are covered with Echini (Fig. 
35) killed in the same way. 
The raven is remarkable for its vocal powers, equaling the parrot. 
The jackdaw, rook, and black-headed crow are other interesting allies. 
The Birds of Paradise (Paradisez) are allies of the 
crows, and confined to New Guinea and the adjacent 
country. In their elaboration of plumage they are the 
most remarkable of all birds. One of the most superb 
forms is the ruby bird of paradise (Paradisea rubra) that 
is found on the Island of Waigiou. They fly in flocks, 
uttering a hoarse and harsh Whack-whack-whack! that 
can be heard for a long distance. They breed in May in 
the North. 
