254 
EDIBLE SWALLOW NESTS. 
with the profit they make by selling them to the Chinese, 
who are the chief purchasers. 
The two bird-mountains above alluded to, are insulated 
rocks, hollow within, and pierced with a great number of 
openings. Many of these openings are so wide, that a 
person can enter them with ease ; others are attended with 
more difficulty, and some are too small to admit of intrusion ; 
in these, therefore, the poor little birds are alone safe from 
robbery. To the walls of these caverns the birds affix their 
small nests in regular rows, and so close that for the most 
part they adhere together. They construct them at different 
heights, from fifty to sixty feet, sometimes higher, some- 
times lower, according as they find room ; and no hole or 
convenient place, if dry and clean, is left unoccupied ; hut if 
the walls he in the least wet or moist, they immediately 
desert them. At daybreak, these birds fly abroad from 
their holes, with a loud fluttering noise, and in the dry 
season rise so high into the atmosphere in a moment, as 
they have to seek their food in distant parts, that they are 
soon out of sight. In the rainy season, on the other hand, 
they never remove to a great distance from their breeding- 
places. 
About four in the afternoon they again return, and 
confine themselves so closely to their holes, that none of 
them are seen any more flying, either out or in, hut those 
which are hatching. They feed upon all sorts of insects 
which hover over stagnant waters, and these they easily 
catch, as they can extend their hills to a great width. They 
prepare their nests from the strongest remains of the food 
which they use, and not of the scum of the sea, or of sea- 
plants, as some persons have supposed. They employ two 
months in preparing their nests ; they then lay their eggs, 
on which they sit for fifteen or sixteen days. As soon as 
the young are fledged, people begin to collect their nests, 
which is done regularly every four months ; and this forms 
the harvest of the proprietors of these rocks. 
The business of taking them down from the rocky ledges 
on which they are placed, is performed by men who have 
