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PHILETAIRUS SOCIUS 131 
The wonderful nest-structures of these birds have been 
figured by Sir Andrew Smith and by Stark, and the former 
naturalist writes: ‘‘ The banks of the Orange River appear to 
constitute the southern limit of this bird’s range; but speci- 
mens were only obtained in great abundance in the district 
around Latakoo, far from water. The most striking peculiarity 
observed of the species is the extraordinary manner in which 
a number of individuals associate, and build their nests under 
a common roof. When a nesting place has been selected, 
and the operation of building the nests is to be commenced 
ab initio, the community immediately proceed conjointly to 
construct the general covering which interests them all; that 
being accomplished, each pair begins to form their own nest, 
which, like the roof, they construct of coarse grass; these are 
placed side by side against the under surface of the general 
covering, and by the time they are all completed, the lower 
surface of the mass exhibits an appearance of an even 
horizontal surface, freely perforated by small circular openings. 
“They never breed in the same nests a second time, 
though they continue for many years attached to the same 
roof. With the return of the breeding season, fresh nests are 
formed upon the lower surface of those of the previous year, 
which then form an addition to the general covering. In this 
manner they proceed, year after year adding to the mass, till at 
length the weight often becomes such as to cause the destruc- 
tion of its support, upon which a new building-place is selected. 
They appear to prefer constructing the nests upon large and 
lofty trees, but where such do not occur, they will even 
condescend to form them upon the leaves of the arborescent 
aloe (Aloe arborescens), as occasionally happens towards the 
Orange River. The commencement of the roof is firmly 
interwoven with the branches of the trees to which it is 
intended to be suspended; and often a great part of a principal 
