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THE ESCULENT SWALLOW. 
and swell, and, when thoroughly dressed, are said to bear some resemblance to rather stiff 
turtle fat. To European palates, however, they appear very insipid, and not worthy of the 
great value which is set upon them by the Chinese. 
It is rather remarkable, that the Esculent Swallows have a habit of building their curious 
nests in horizontal layers. 
The substance of which these nests are composed is evidently of an animal nature to some 
extent, although certain vegetable matters, such as the gelatinous fuci or sea- weeds may be 
admixed with it. Whatever may be the basis of the nutriment that forms these nests, it 
ESCULENT SWALLOWS.— Collocalia nidifica. 
is clear that a very large portion of it is furnished by certain glands, which pour out a 
viscid secretion. 
The trade in these strange articles of diet is a very large one, and still holds its ground, 
the annual weight of nests that is obtained from the various caves in which the Esculent Swal- 
lows take up their residence being upwards of fifty thousand pounds, and the value of the 
goods more than a million dollars. In the Philippine Islands the bird is called the 
Salangana. The tribe of the genus Collocalia approach very nearly to the true Swallows in 
their structures, but have many points which are identical with the Swifts. The second 
primary feather is the largest, the first three toes point forward, and the fourth toe backward, 
and the tail is moderate in length. 
The nests are harried about three times in every year, and it is said that the natives who 
rre employed in procuring them are careful to destroy the old and deep-colored nests, in order 
fco force the birds to build new habitations, which command a high price in the market. The 
