56 THE ARCHITECTURE OF BIRDS. 
The best-known nest of this description is that of 
the cushat, ring-dove, or wood-pigeon (Columba Pa- 
lumbus, Linn.). The nest of this birdis a very slight 
structure, and still less calculated for warmth or 
shelter, the hot nature of the parent birds, according 
to Albertus Magnus, not requiring this. It may, with 
the utmost propriety, be called a platform, being com- 
posed of a flat pile of twigs, not artfully interwoven, 
as is stated in some books, but laid crossways upon 
one another in a rather loose manner, though not 
without neatness and attention to symmetry; for, 
when completed, the structure is always very nearly 
circular. ‘The Jarger and longest twigs are. laidas a 
foundation, the sizes chosen becoming smaller as 
the work advances. It is mentioned that in some 
instances the eggs may be seen through the twigs 
from below. 
The American pigeons are also platform builders ; 
for example, the Carolina pigeon (Columba Caroli- 
nensis), which, according to Wilson, commences 
building about the beginning of May, the nest being 
*‘ very rudely constructed, generally in an evergreen, 
among the thick foliage of the vine, in an orchard 
on the horizontal branches of an apple-tree, and in 
some instances on the ground. It is composed of 
small twigs, laid with little art, on which are scat- 
tered dry fibrous roots of plants, and in this almost flat 
bed are deposited two eggs of a snowy whiteness.”* 
A similar mode of building is practised by the 
American passenger pigeon (Columda migratoria), 
the most prolific of the whole family, and perhaps 
of all other birds, if the numbers reared be regarded, 
though it seems to be ascertained that the female 
only lays a single egg at one hatch. ‘This singular 
bird inhabits a wide and extensive region of North 
America, though it does not seem to be known 
westward of the Great Stony Mountains; but 
spreads all over Canada, and ranges as far south 
as the Gulf of Mexico. 
* Wilson’s Amer. Ornith., v., 93. 
