The Spectacled Weaver is a species of Southern African bird in the Ploceidae family which includes birds such as Weavers, Queleas, Widowbirds
Visual Traits Female preferences for long tails in long-tailed widowbirds (Euplectes progne).
Female choice selects for extreme tail length in a widowbird.
Additional chapters include descriptions of bustards (arid-adapted Old World species); kakapos (a New Zealand nocturnal parrot), hummingbirds, and lyrebirds (Australian mimics); and African long-tailed whydahs and widowbirds
On the other hand, the same trait may be favored by different types of sexual selection in different species; for instance, in one species of widowbirds (Euplectes progne), the long tails of males influence female choice but not the outcome of contests between males (Andersson 1982), whereas the converse is true in a congener (E.
Tail length affects territory ownership in the yellow-shouldered widowbird.
Sexual dimorphism and modes of sexual selection in lekking Jackson's widowbirds
Euplectes jacksoni (Ploceinae).
with experimentally exaggerated tails had higher reproductive success (Andersson 1982).
Examples of this approach involve adjusting clutch size (references above), tail length in widowbirds
(Andersson 1982), or offspring size by yolk removal from eggs (Sinervo and McEdward 1988; Sinervo 1990; Sinervo and Huey 1990).
Most recently, across 14 species of widowbirds and bishops (genus Euplectes), Andersson and Andersson (1994) have demonstrated that sexual dimorphism in wing length is independently related not only to dimorphism in body size but also to sexual dimorphism in tail length and to the incidence of display flights.
For instance, estimates for Jackson's widowbird Euplectes jacksoni suggest that its long tail could increase flight costs by more than 300% (Thomas 1993).
Male tail length among the 16 species of widowbirds
and bishops (genus Euplectes) varies considerably, from 3 to 50 cm (females are cryptically colored and have short tails), and recent evidence from three of these is consistent with the hypothesis that their long tails are adaptations arising from sexual selection (M.