BOHEMIAN WAXWING. 
463 
rally close together, many are easily killed at once by a single 
discharge of a gun. They always alight on trees, hopping 
awkwardly on the ground. Their flight is very rapid : when 
taking wing, they utter a note resembling the syllables, zi^ zi, 
ri, but are generally silent, notwithstanding the name that has 
been given them. They are, however, said to have a Sweet 
and agreeable song in the time of breeding, though at others 
it is a mere whistle. The place of breeding, as we have inti- 
mated, is not known with any certainty, though they are said 
to build in high northern latitudes, preferring mountainous 
districts, and laying in the clefts of rocks, which, however, 
judging from analogy, we cannot believe. 
What can be the cause of their leaving their unknown abodes, 
of their wide migrations, and extraordinary irruptions, it is 
very difficult to determine. That they are not compelled to 
them by cold is well proved. Are they to be ascribed to ne- 
cessity from excessive multiplication, as is the case with the 
small quadrupeds called lemmings, and even with man himself 
in a savage state, or in over populous countries ? or shall we 
suppose that they are forced by local penury to seek elsewhere 
the food they cannot be supplied with at home ? Much light 
may be thrown on the subject by carefully observing their 
habits and migrations in America. 
The Bohemian chatterer being so well known, we shall here 
only give a description of our best American specimen, which 
is a female shot on the 20th March, 1825, on the Athabasca 
river, near the Rocky Mountains. The sexes hardly differ in 
plumage. 
Length, eight and a half inches ; extent, fifteen ; bill, three 
quarters of an inch long, black, paler at the base of the under 
mandible ; irides, reddish, often quite red ; nostrils, entirely 
uncovered. From the base of the ridge of the bill arises, on 
each side, a velvety black line, bordering the forehead, and 
spreading on the ophthalmic region, and surrounding almost 
the whole crown ; throat also deep black. The anterior part 
of the head is bright bay, behind passing gradually into vina- 
