CLASS II. AVES: ORDEE 2. PASSERES. 91 
THE COMMON EUROPEAN SWIFT. 
these birds, young and old, were precipitated down a single chimney in Woodbury, Connecticut. 
In this case all died, but often the young scramble up along the vent, to which they cling like 
squirrels, the muscularity of their feet, and the sharpness of their claws being remarkable. 
The Common Swift of Europe, C. apus, resembles the preceding in form and manner of flight, 
but it builds in cavities under the eaves of houses, in holes about steeples, old towers, and walls. 
The Alpine Swift, C. Alpinus, surpasses other species in speed, and feeds on insects very high 
in the air. It is found in summer in the high mountains of Southern Europe, and has been occa- 
sionally found in Great Britain. Its length is eight inches and a half. 
Genus COLLOCALIA: Collocalia. — This includes the Esculent Swallow, C. esculenta, the 
fabricator of the celebrated birds' nests which enjoy such a high repute among the Chinese for 
their excellence as an article of food. These are composed of a mucilaginous substance, usually 
more or less mixed with fragments of grass, hair, and similar materials ; they are attached to the 
surface of rocks in caverns, and the birds always build in great numbers together in the same 
cave. It was formerly supposed that the mucilaginous matter employed in the construction of 
the nests was obtained from sea-weeds eaten by the birds, but it is now ascertained beyond doubt 
that the substance in question is secreted by greatly developed salivary glands. These birds are 
found in great abundance in all parts of the Eastern Archipelago, and also on the continent of 
India; the nests are collected in great quantities, and constitute an important article of commerce 
with China. Almost all our knowledge of the mode in which the harvest of nests is managed is 
derived from the island of J ava, which produces about two hundred and fifty-six hundred weight 
annually. The nests are collected in Java at three different periods, namely, in March, Septem- 
ber, and December. The interval of six months, from March to September, gives the birds time 
to rear two broods, and the quantity of nests is consequently greater than at the other two periods 
of collecting, but the produce is generally of inferior quality; the lesser intervals between the 
collection in September and that in December, and again between the latter and that in March, 
scarcely allows the birds to get their progeny out of the nests, and many young ones are accord- 
ingly destroyed at these periods, but the nests are of superior quality, and very white. The prices 
paid for these nests in the Canton market vary greatly, according to the quality : those of the 
best and purest sort fetch the enormous price of three thousand five hundred Spanish dollars the 
pecul, or about twenty-five dollars a pound ; the second quality brings two thousand eight hun- 
dred Spanish dollars per pecul, and the third not more than one thousand six hundred dollars. 
In some parts of China, however, as much as forty dollars has been paid for a catty of bird's nests, 
or rather more than one pound and a quarter. These expensive articles are principally employed 
in making soup, but they are also made use of in various ways, and are regarded as a great deli- 
cacy by the Chinese epicures. 
