The long-tailed widowbird (Euplectes progne) is a species of bird in the weaver family Ploceidae.Mackworth-Praed, C.W., and C.H. Grant. (1960). Birds of Eastern and North Eastern Africa. Longmans, Green and Co LTD.; London The species is found in Angola, Botswana, the Democratic Republic of the Congo, Kenya, Lesotho, South Africa, Eswatini, and Zambia.Hall, B. P. and R. E. Moreau. (1970). An atlas of speciation in African passerine birds. British Museum of Natural History, London. The long-tailed widowbird is a medium-sized bird and one of the most common in the territories it inhabits.Andersson, M. (1982). "Female choice selects for extreme tail length in a widowbird." Nature, 299: 818–820. Adult breeding males are almost entirely black with orange and white shoulders ("epaulets"), long, wide tails, and a bluish white bill. Females are rather inconspicuous, their feathers streaked tawny and black with pale patches on the chest, breast and back, narrow tail feathers, and horn-coloured bills.
When flying, male long-tailed widowbirds are readily visible due to their extremely long tails. Between six and eight of their twelve tail feathers are approximately half a metre (approximately 20 inches) long. The tail during flight display is expanded vertically into a deep, long keel below the male as he flies with slow wingbeats 0.5 to 2 metres (20 to 78 inches) above his territory.
Because of the seemingly large cost to such male ornaments, the long-tailed widowbird has been the subject of extensive research into the function and evolution of sexually selected traits. This research has demonstrated the existence of female choice in sexual selection and indicates the trade-offs between sexual appeal and physical constraints with regard to the evolution of sexual ornaments.
Taxonomy The long-tailed widowbird was described by the French polymath Georges-Louis Leclerc, Comte de Buffon in 1779 in his Histoire Naturelle des Oiseaux from a bird collected in the Cape of Good Hope region of South Africa. The bird was also illustrated in a hand-coloured plate engraved by François-Nicolas Martinet in the Planches Enluminées D'Histoire Naturelle which was produced under the supervision of Edme-Louis Daubenton to accompany Buffon's text. Neither the plate caption nor Buffon's description included a scientific name but in 1783 the Dutch naturalist Pieter Boddaert coined the binomial name Emberiza progne in his catalogue of the Planches Enluminées. The long-tailed widowbird is now one of 17 species placed in the genus Euplectes that was introduced by the English naturalist William Swainson in 1829. The genus name combines the Ancient Greek eu "fine" or "good" and the Neo-Latin plectes "weaver". The specific progne is Latin for a "swallow.
Three subspecies are recognised: E. p. delamerei (Shelley, 1903) – central Kenya E. p. delacouri Wolters, 1953 – Angola, south DR Congo and Zambia E. p. progne (Boddaert, 1783) – southeast Botswana to east South Africa
The long-tailed widowbird has three geographically differentiated subspecies. These include delamerei, found in the highlands of Kenya, delacouri, found in the Congo, Angola and Zambia, and progne, found in Botswana, South Africa, Eswatini and Lesotho.Craig, A. (1993). Geographical variation and taxonomy of the genus Euplectes (Aves Ploceidae). The long-tailed widow birds. Revue de Zoologie Africaine 107(2): pp. 139–151. Some researchers have suggested the existence of long-tailed widowbird superspecies based on similarity in male nuptial plumage such as tail length, but this is the topic of some debate.Andersson, S. and Andersson, M. (1994). Tail ornamentation, size dimorphism and wing length in the genus Euplectes (Ploceinae). The Auk 111: pp. 80–86.
Description Long-tailed widowbirds exhibit distinct sexual dimorphism. Males and females exhibit differences in behaviour and morphological traits. Adult males are entirely black, including under their wing-coverts. Males' wing shoulders are orange red and their wing-coverts white. Their bills are bluish white. Males are known for their distinctly long tails, which contain twelve tail feathers. Of these twelve tail feathers, between six and eight are approximately half a metre (approximately 20 inches) long. Males have wingspans of approximately 127 to 147 mm (approximately 5 to 5.8 inches).
Females have a rather subdued colours. The upper portion of the female's body is streaked with buff or tawny and black. Female chests, breasts and flanks are slightly paler than their above colouring. The area under the wing-coverts is black and the females' tail feathers are narrow and pointed. Finally, their bills are horn-coloured.
Non-breeding males are slightly larger than females, though they demonstrate a remarkably similar appearance. For the most part, these males are coloured in the same manner as the females, except in that they are more broadly streaked above and below and have wings and wing shoulders with the morphology of the breeding class of males. Rarely, males in the non-breeding class have elongated brownish black tail feathers, though these feathers are substantially shorter than those of the breeding class.
Immature males and females are very similar in appearance to the adult female. However, immature males, much like adult non-breeding males, are slightly larger than adult females.
The length of a female starts at 15 cm and males have been recorded at 71 cm in length, which has their tail included. Male weigh between 33–46 g and females weigh between 25–39 g.
Distribution and habitat There are three known isolated populations of long-tailed widowbirds. The first is found in the Kenyan highlands, the second in Angola, southern Zaire and Zambia, and the third in southern Africa. It is unknown when these populations were last in contact, however, and the central population differs most in morphology relative to the other two populations.Craig, A. (1980) "Behaviour and evolution in the genus Euplectes." Journal of Ornithology, 121: 144–161. The southern African population extends from the Eastern Cape (Transkei region) through the Free State, Lesotho, KwaZulu-Natal, and western Eswatini to the Transvaal plateau. The species just enters southeastern Botswana, but is most commonly found in the central highveld of South Africa.
Long-tailed widowbirds are generally found in swampy grassland in flocks consisting of one or two males and a number of females. The males fly with their tails drooping and somewhat spread, and with slow regular movements of their wings. In wet weather, they are unable to fly due to their elongated tails. During the non-breeding season, long-tailed widowbirds congregate into flocks, which can be found roosting in reed beds. The long-tailed widowbird can be found at elevations up to 2,750 metres (9,022 feet) in the Drakensberg Mountains.Andersson, Malte. (1994). Sexual Selection. Princeton University Press; Princeton, NJ: pp. 112–117.
Behaviour Food and feeding The long-tailed widowbird's diet generally consists of seeds, supplemented occasionally by arthropods. The birds do most of their foraging in flocks on the ground, though they are occasionally observed hawking insects airily.Hockey, P.A.R, Dean, W.R.J. and P.G. Ryan. (2005). Roberts' Birds of Southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund; Cape Town. The long-tailed widowbird feeds on a distinct variety of seeds, including those of Setaria sphacelata (twisted-leaf bristle grass), Paspalum dilatatum (common paspalum), Paspalum distichum (couch paspalum), Pennisetum clandestinum (Kikuyu grass), Triticum (wheat), Themeda triandra (rooigras), and Senecio juniperinus (groundsel). They also feed upon both insects, including species of beetles (Coleoptera), cicadas and aphids (Hemiptera), and spiders.Hockey P., Dean W. and Ryan P. (2005). Roberts – Birds of southern Africa, VIIth ed. The Trustees of the John Voelcker Bird Book Fund, Cape Town.
Breeding Males defend territories in the grasslands the species inhabits. Females have a long nesting period and survey these territories and the males that inhabit them prior to mate selection. Breeding takes place from February to July, reaching its peak in March and April. Females weave nests, shaped in large dome structures with a lining of seedheads, in the high grass within males' territories. The nests are placed 0.5–1 meters (19 to 40 inches) off the ground in the upper third of the high grass (Eleusine jaegeri), where the females raise their two to three young. Females often mate with the male within whose territories they nest. Females lay one to three eggs after mating, and these are pale bluish green and streaked with brown. They are usually around 23.5 millimeters (0.9 inches) by 16.5 mm (0.6 inches) in size.
Sexual selection Charles Darwin first expressed his ideas on sexual selection and mate choice in his book The Descent of Man, and Selection in Relation to Sex in 1871 in response to questions surrounding the elaborate ornamentation that males of some species exhibit despite detrimental costs to survival and seemingly negative consequences for reproductive success.Darwin, C. (1871). The Descent of Man, and Selection in Relation to Sex. John Murray; London. He proposed two explanations for such traits' existences: these traits are useful in male-male combat or are preferred by females.
Relative to the first of Darwin's theories on sexual selection, the process of female choice, though theoretically plausible, took a considerable amount of time to gain acceptance because Darwin had little, if any, firm evidence that females did in fact choose mates based on characteristics they found attractive.Fisher, R.A. (1930). The Genetical Theory of Natural Selection. Clarendon Press, Oxford.Maynard-Smith, J. (1958) in A Century of Darwin (ed. Barnett, S.A.). Heineman; London: 231–245. It took ninety years after Darwin's initial proposal for the theory to be tested in what has become a classic example of behavioural ecology research.Davies N, Krebs J, and West S. (2012). An Introduction to Behavioural Ecology, 4th Ed. Wiley-Blackwell; Oxford: pp. 188–192.
The male long-tailed widowbird has one of the most remarkable ornaments among passerine birds. Their tails, which are often more than half a meter (20 inches) long, are the most extreme sexual ornament among Euplectes and seem to in fact be detrimental to the survival of the male. Thus, the tail appears to oppose forces of natural selection in the basic sense by decreasing survival in individuals who carry the trait. It was for this reason that researchers have chosen to focus their research into female choice on the confusing example of the long-tailed widowbird.
Andersson experiment