THE BREEDING HABITS OF THE WEAVERBIRDS 
A STUDY IN THE BIOLOGY OF BEHAVIOR PATTERNS 
By HERBERT FRIEDMANN 
Curator, Division of Birds, 
U. S. National Museum 
[With 8 plates] 
The weaverbirds, as their popular name implies, are, by and large 
birds noted for the elaborate nests they build—in many cases actually 
weave—out of grasses, straws, rootlets, and other similar materials. 
Included in this family (Ploceidae) are some of the finest, most expert, 
and most famous of all avian architects. In no other single bird 
group of similar status has the habit of nest building been carried to 
greater heights, indeed their only rivals for excellence in this particular 
are some of the hang-nests or troupials of the New World. 
My interest in the weaverbirds began some 30 years ago when I had 
the opportunity of studying the actual weaving methods in captivity 
of one species, the red-billed weaver, Quelea quelea. Not long after- 
ward when I began my studies of parasitic birds I learned that at 
least two species of weavers, and possibly several others, not only 
built no nests at all, but laid their eggs in the occupied nests of other 
kinds of birds to whose care the eggs and the subsequent young were 
left. A few years later, over a year’s field work in South and East 
Africa gave me ample opportunity to become familiar with the surpris- 
ing range of aspects the nest-building habit exhibits in this family of 
birds. In this paper it is not my purpose to attempt to describe each 
and every one of these aspects, but to discuss them from the point of 
view of the biological implications they present. ‘The family is a 
large and varied one and contains a great many species (about 275), 
many of which have highly divergent nesting habits, which offer very 
suggestive data to the naturalist concerned with the evolution of 
habits in birds. 
In order to appreciate more adequately the significance of the 
various aspects of the nest-building habit in these birds, and to 
evaluate them more properly in connection with other parts of the 
life histories of birds involved, it is necessary to make a few preliminary 
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