The behaviour of male yellowmantled widowbirds euplectes macrourus in western kenya
TL;DR: During the breeding season, male Yellowmantled Widowbirds defend territories from conspecifics but do not exclude Marsh Widowbirds E. hartlaubi, and during the non-breeding season they form mixed species flocks with other finches.
Abstract: Summary Savalli, U. M. 1993. The behaviour of male Yellowmantled Widowbirds Euplectes macrourus in western Kenya. Ostrich 64: 57–62. Male Yellowmantled (Yellowbacked) Widowbirds Euplectes macrourus use two displays in territorial defense. The territory boundary display involves a specific, upright posture along with the hiss-trill vocalization, but the song does not have a visual component. Courtship displays involve flicking up the wings and tail, sometimes leaning toward the female with the tail elevated, and a slow, bouncing flight display. The swivelling display described by Emlen (1957) was not observed, and seems to be replaced by the flicking displays. During the breeding season, male Yellowmantled Widowbirds defend territories from conspecifics but do not exclude Marsh Widowbirds E. hartlaubi. At night they form communal roosts off their territories. During the non-breeding season they form mixed species flocks with other finches. Male widowbirds are most active in display before 10h00, and often ...
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TL;DR: The extant empirical and theoretical work regarding heterosexual human mating preferences and reproductive strategies are reviewed, focusing on the adaptive significance of material, genetic and fertility benefits, and their relationship to environmental characteristics.
Abstract: The recent incorporation of sexual selection theories into the rubric of evolutionary psychology has produced an important framework from which to examine human mating behavior. Here we review the extant empirical and theoretical work regarding heterosexual human mating preferences and reproductive strategies. Initially, we review contemporary evolutionary psychology's adaptationism, including the incorporation of modern theories of sexual selection, adaptive genetic variation, and mate choice. Next, we examine women's and men's mating preferences, focusing on the adaptive significance of material, genetic and fertility benefits, and their relationship to environmental characteristics. Following this, we consider human mate choice in relation to non-adaptive preferences. This discussion ends with a look at context effects for individual differences in mate-preferences and reproductive strategies.
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...Other studies have examined behavioral traits as fitness indicators that predict mating success and offspring viability; these include call duration in grey tree frogs (Gerhardt, Tanner, Corrigan, & Walton, 2000; Welch, Semlitsch, & Gerhardt, 1998), song complexity in thrush nightingales (Amrhein, Korner, & Naguib, 2002) and nightingale grasshoppers (Klappert & Reinhold, 2003), frequency and duration of courtship display in dung beetles (Kotaiho, 2002), and nest building in widowbirds (Savalli, 1993) and bowerbirds (Borgia, 1985, 1995)....
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...…1998), song complexity in thrush nightingales (Amrhein, Korner, & Naguib, 2002) and nightingale grasshoppers (Klappert & Reinhold, 2003), frequency and duration of courtship display in dung beetles (Kotaiho, 2002), and nest building in widowbirds (Savalli, 1993) and bowerbirds (Borgia, 1985, 1995)....
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TL;DR: Examination of correlates of male attractiveness to nesting females over two breeding seasons for the polygynous yellow-shouldered widowbird found which cues females may be using to select mates, including tail length, was the best predictor.
Abstract: Recent investigations of male ornaments in sexual selection have used experimental manipulation of tail length in three widowbird species, but only for one of these have correlates of male reproductive success been reported. I examined correlates of male attractiveness to nesting females over two breeding seasons for the polygynous yellow-shouldered widowbird, Euplectes macrourus, in order to discover which cues females may be using to select mates. The black, long-tailed (≈ 10 cm) males defend large territories and build nest frames, or cock's nests, which females then line and use for nesting. I examined various aspects of male morphology, five behavioral displays, territory characteristics, and the number of cock's nests that males built. Few correlates of mating success were found. The best predictor was the number of cock's nests that a male builds, though one courtship display also correlated with male mating success in 1 year, as did average grass height. Tail length did not correlate with male mating success. A partial correlation analysis confirmed that cock's nests and, in 1 year, grass height, were the primary contributers to male success. Females may choose where to nest primarily on the availability of suitable nesting sites. Long tails may be used by females seeking extra-pair copulations or in male-male competition for territories.
25 citations
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...The following displays were recorded (all are described in more detail in Savalli 1993): 1....
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...Interestingly, the crouch-flicking display, which appears to be a more intense form of the wing/tail flick (Savalli 1993), did not have a similar effect....
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TL;DR: Males were larger than females, with wing length the best single measure to distinguish sex (since immature males are streaky brown, like females), and the breeding sex ratio was nearly even in one year but heavily male biased the second, suggesting that not all females may breed.
Abstract: Summary Savalli, U.M. 1994. Sexual dimorphism and sex ratio in the Yellowshouldered Widowbird Euplectes macrourus soror. Ostrich. 65: 297–301. Yellowshouldered (Yellowbacked) Widowbirds Euplectes macrourus soror are sexually dimorphic in plumage and size. At Kakamega, western Kenya, adult males were all black except for the yellow shoulders, contrary to previous reports that yellow-mantled individuals were predominant in this area. Males were larger than females, with wing length the best single measure to distinguish sex (since immature males are streaky brown, like females). Immature males had shorter wings and tails than did adult males, but did not differ in other measures of size. The sex ratio of netted birds was near 1:1, but nearly half of the males were immature. The breeding sex ratio was nearly even in one year but heavily male biased the second, suggesting that not all females may breed.
4 citations
Dissertation•
28 Mar 2008
4 citations
Cites background from "The behaviour of male yellowmantled..."
...…2007, Searcy et al. 2006, Aubin et al. 2004, Bee & Gerhardt 2002, Jaeger et al. 1996, Kroodsma & Byers 1991) ou exibições sinalizando ameaça (Kohn et al. 2005, Markus 2002, Gese 2001, Savalli 1993, Schwab & Stout 1991, Simpson 1968); aspectos estes revisados em Stamps 1994 e Davis & Houston 1984....
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TL;DR: Observations that males frequently fed outside their territories and formed communal roosts during the breeding season suggest that this species represents a transitional stage between typical resource-defence polygyny and lek breeding.
Abstract: The territorial system and breeding biology of the Yellow-shouldered Widowbird Euplectes macrourus (Ploceidae) was investigated in western Kenya. Yellow-shouldered Widowbirds had a resource-defence polygynous mating system: males defended large (mean = 0.95 ha) territories and built the coarse framing for the nests in tall grass. Males had up to five females nesting per territory. Females provided nearly all parental care except for a territorial male seen feeding a fledgling: the first observation of paternal care in the wild for this genus. There was considerable variation in territory size, but the cause of this variation remains unknown: territory size was not related to potential indicators of territory quality, such as grass height and abundance, did not relate to male morphology (mass, size and ornament size) or territorial behaviour (boundary displays and singing) and did not affect female preferences. Although resources (territories and nests) were defended by the males, observations that males frequently fed outside their territories and formed communal roosts during the breeding season suggest that this species represents a transitional stage between typical resource-defence polygyny and lek breeding.
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TL;DR: It is reported here that males in which the tail was experimentally elongated showed higher mating success than males having normal or reduced tails: males with shortened tails held their territories as long as did other males.
Abstract: Darwin's1 hypothesis that male secondary sexual ornaments evolve through female preferences is theoretically plausible2–7, but there is little experimental field evidence that such preferences exist8–10. I have studied female choice in relation to male tail length in the long-tailed widowbird, Euplectes progne, and report here that males in which the tail was experimentally elongated showed higher mating success than males having normal or reduced tails. The possibility that intrasexual competition among males maintains the long tail was not supported: males with shortened tails held their territories as long as did other males. These results suggest that the extreme tail length in male long-tailed widowbirds is maintained by female mating preferences.
823 citations
TL;DR: Investigation of sexual selection in the lekking Jackson's widowbird found that tail length was positively related to a measure of body condition, which is of interest with regard to the suggestions that sexual ornaments may serve as indicators of male viability.
Abstract: Sexual selection through female mate choice was investigated in the lekking Jackson's widowbird by applying multivariate selection analysis to observational data from four leks. Males perform a stereotyped jump display on small display courts (“dance rings”) constructed by the males in open grassland. Females visit the lek solely for mating and nest on their own, away from the lek area. Few cases of interference during courtship and absence of position effects on mating success indicated that female choice within the leks was not pre-empted by male-male competition. In a set of 11 male traits with mating success as the dependent fitness measure, significant selection differentials (covariances) were found for the length of the conspicuous tail and the rate of the jump display, suggesting sexual selection of these traits. They also showed the largest selection gradients (partial effects) and thereby seem to be the cues on which females base their choice. The success of males in obtaining copulations appears to depend on two components: display rate and lek attendance affect the number of female visits, whereas tail length seems to primarily influence the chance of copulating with a visiting female. Tail length was positively related to a measure of body condition, which is of interest with regard to the suggestions that sexual ornaments may serve as indicators of male viability.
121 citations
TL;DR: The evolution of the genus is discussed; the two main behavioural changes have been an elaboration of the flight display, accompanied by a decline in nest-building by the ♂.
Abstract: TheEuplectes species are polygynous weavers, showing marked sexual and seasonal dimorphism. The ♂ are territorial during the breeding season, and interspecific territorial behaviour is common. Courtship consists of a flight display followed by a perched display leading to copulation. The nest plays an important role in courtship. Throughout the year the birds feed and roost in large aggregations. The evolution of the genus is discussed; the two main behavioural changes have been an elaboration of the flight display, accompanied by a decline in nest-building by the ♂.
47 citations