2 
n. Il^TItODUCTION. 
In tJie archifcecture of the nests of many birds a secretion of the salivary 
glands plays a part but it remains for some members of the famil>- Microjiidae, or 
Bwifts, to make their uests largely or wholly of inspissated saliva which hardening 
into a substance not unlike isingiass on its exposure to the air forms the " edible 
birds* nests " of commerce. These nests are in great demand by epicures, chiefly 
Chinese^ by whom they are supposed to be aphrodisiacal. 
It is a fortuitous but fortunate circumstance for North Borneo that the birds 
providing the nests elect to nest in largo colonies in that country. 
Technically, the nests in the caves of Nortli Borneo are produced b\- four 
species of swiftlet (a name of no real significance but merely a popular diminutive 
of swift*). These are all of the genus CollocaUa, a division of the CkaetuHnae 
which is a subfamily of the Micropidae containing in atldition to the Swiftlets '* 
the well known spine-tailed swifts, one of which is sup[>08ed to be the fastest bird 
in the world. 
The nests are collected by natives at regular intervals and eventually exported 
from the country, mainly to China. The Government profits by the export tax 
paid on the nest and by the reception of a variable royalty. The industry appears 
to be permanent and it is lucrative to all parties. 
*0n no account nmet " swullow" be gubstitututl for swift or Bwiftlet. 
