310 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1949 
macroura is parasitic chiefly on waxbills and generally lays but one 
egg ina nest. I have seen sets containing two, three, and even, four 
of the widow bird’s eggs along with those of the victims, but such 
sets are not usual. The eggs are pure white and differ from those of 
the common fosterers only in size. 
The following birds have been found to be parasitized by Vidua 
macroura: 
Lonchura scutatus Estrilda rhodopyga 
Estrilda astrild Estrilda delamerei 
Estrilda subflava Lagonosticta senegala 
Estrilda melpoda Lagonostica rubricata 
Estrilda massaica Amauresthes fringilloides 
Estrilda melanotis Coliuspasser ardens 
The incubation period is 12 days. 
The breeding season in South Africa is late in the southern summer— 
January, February, and early March, sometimes earlier. In Kenya 
Colony the species breeds during both the short and the long rainy 
seasons. The short rains come in November, December, and Jan- 
uary; the long rains in April, May, June, and July. As one goes 
northward the rains shift to later in the calendar year; thus in the 
southern Sudan the long rains extend into September and start 
correspondingly later than in Kenya Colony. 
The young V2dua does not always crowd out or starve out its nest 
mates (at least in the few cases I watched) as do the young cuckoos 
and cowbirds in so many cases, but all grow up together. Fully 
fledged young Vidua macroura are often found in flocks of young 
waxbills after leaving the nest but they do not remain long in these 
assemblages. Before they get ready to molt (postjuvenal molt) 
they form flocks of their own. I have seen as many as 15 or 20 
young pin-tailed widow birds together. Frequently one or two adult 
birds, often males in breeding plumage, are found in these flocks. 
My observation on Vidua regia, the shaft-tailed widow bird, Vidua 
jischeri, the straw-tailed widow bird, and Vidua orientalis, one of the 
indigo finches, while much less complete than those on Vidua macroura, 
also indicate that the superficially apparent polygamy is actually not 
real, that while one male in adult breeding plumage may be accom- 
panied by a small flock of brown henlike individuals, most of the 
latter are immature birds of both sexes and only one in a group may 
be an adult female. In the case of the straw-tailed widow bird, 
Vidua fischeri, I once observed what seemed to be a territorial fight 
between two males in full breeding plumage. 
To summarize the behavior-pattern cycle in the Viduinae, we may 
characterize it as follows: apparently monogamous and solitary(?), but 
solitary only with respect to its own age group (adults), not solitary 
