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  • 1
    Electronic Resource
    Electronic Resource
    Fine-scale genetic structuring on Manacus manacus leks (2000)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 408 (2000), S. 352-353 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Leks have traditionally been considered as arenas where males compete to attract females and secure matings. Thus, direct fitness benefits mediated through competition between males to fertilize females have been considered to be the primary force driving the evolution of lekking ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35042562
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  • 2
    Electronic Resource
    Electronic Resource
    Lekking in the black grouse— a test of male viability (1991)
    [s.l.] : Nature Publishing Group
    Nature 352 (1991), S. 155-156 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Black grouse males were caught at a feeding site in central Finland (Petajavesi, 62°10' N, 20°05' E) during the winters of 1987-90, and marked individually with colour rings. Copulations were recorded on the four leks within 3 km of the site of capture, in late April and early May11'12 each ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/352155a0
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  • 3
    Electronic Resource
    Electronic Resource
    Egg predation in forest bird communities on islands and mainland (1985)
    Springer
    Oecologia 66 (1985), S. 511-515 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To examine if differences in egg predation rates could explain differences in bird community composition, egg predation was studied in two years on small islands in a South Swedish lake and on the nearby mainland using both natural and artificial nests. In plots with similar vegetation, the combined density of ground- and tree-nesting bird species did not differ between the islands and the mainland. Egg predation rates were similar on islands and the mainland for natural Turdus nests in two years, and for artificial Turdus and Phylloscopus nests. Unmarked and unvisited experimental nests suffered similar rate of egg predation as marked and visited nests. Egg predation rates were higher on natural nests when artificial nests were also put out, increasing the total nest density. Initial egg predation rates in artificial nests were also higher than later when nest density had decreased by 75%. The egg predators involved differed for artificial Phylloscopus nests between the islands and the mainland. Small mammals were apparently responsible for 29% of the predation on the mainland, but none on the islands. Artificial Turdus nests near crow nests suffered from a higher egg predation rate than nests further away from crow nests. Daily survival rates of Turdus nests increased from the laying to the incubation and further to the fledging state. Egg predation can not explain differences in bird community composition between islands and mainland in the present case.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379342
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  • 4
    Electronic Resource
    Electronic Resource
    Nesting holes and food supply in relation to forest bird densities on islands and mainland (1985)
    Springer
    Oecologia 66 (1985), S. 516-521 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Bird densities were estimated on 41 small islands and two mainland plots at a South Swedish lake both in 1976 and 1983. In the latter year, three additional plots were also censused. The ratio between combined densities of hole-nesting birds on the mainland and on islands was 3:1 both in plots without and with nest boxes. In plots with boxes combined densities of hole-nesting birds doubled compared with control plots. This increase was caused by a tenfold increase of pied flycatcher Ficedula hypoleuca. Territories of this species were on average established about a week later on the islands compared with the mainland. Furthermore, 50% of the males on the islands did not attract a female. Densities of great tit Parus major, marsh tit Parus palustris and nuthatch Sitta europaea were unaffected by increased nesthole availability. For P. major this result contrasts with those in other studies. The density of chaffinch Fringilla coelebs in habitats with similar height and vertical structure was two times higher on the islands compared to the mainland. On the islands the density was the same on islands with only one pair and on those with two or more pairs. In spring, there were no significant differences between islands and the mainland in the proportion of leaves with insect feeding traces. The proportion of Salix leaves with feeding traces increased with island size, but this was not so for Alnus and Betula leaves. In late summer, the proportion of leaves with feeding traces were halved inside a plot with nest boxes and hence increased bird densities compared to a nearby control plot. This result was the same along the lake shore and about 150 m away from the shore. The discussion centers on the effect of man on the food-and nest site-availability of hole-nesting birds, food limitation of insectivorous birds and density compensation on islands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379343
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  • 5
    Electronic Resource
    Electronic Resource
    Spacing of leks in relation to female home ranges, habitat requirements and male attractiveness in the great snipe (Gallinago media) (1990)
    Springer
    Behavioral ecology and sociobiology 26 (1990), S. 173-180 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In an attempt to examine three main hypotheses on the evolution of leks, data on female home ranges, distance between leks and male site fidelity in the great snipe (Gallinago media) were obtained. In a 30 × 40 km area in central Sweden, the locations of 12 leks were identified. Six were within the study area (7 × 11 km) in which probably all leks were known. In the study area, nearest neighbor distances between leks were longer than the predicted drawing area (diameter of female home ranges plus the detection range of leks). Furthermore, in only 1 of 13 radio-tracked females did the estimated home range enclose many leks. These data do not fit the prediction from the hotspot hypothesis on the dispersion of leks, namely, that the distance between leks should be less than the drawing area and hence an average female home range should enclose more than one lek. The observed distance between leks was about the same as predicted by the female preference hypothesis. This hypothesis also predicts females visit mainly one lek; however, we found they sometimes visit two and nest close to a third. We propose that males may first settle according to hotspot rules, but females will resettle according to preferences for certain males and/or larger leks. In this way some hotspot leks are abandoned, and the distance between leks is increased as males become more tightly clumped. However, when all males and females have settled, the leks still existing would be on hotspots. In the female preference hypothesis, males are assumed to aggregate on leks because females prefer clustered males as they can be more easily compared than if they are dispersed. Alternatively, in the attractiveness hypothesis, it is suggested that females prefer certain males, and hence unattractive males surround the attractive are forced to join leks in order to come close to females. Our data on male site fidelity support the attractiveness hypothesis because successful and dominant males return to the same lek and territory, both within and between years, whereas unsuccessful males move to other leks. Attractiveness of certain males may explain why according to hotspot rules in this species males are more clumped than expected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172084
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  • 6
    Electronic Resource
    Electronic Resource
    Costs and consequences of variation in the size of ruff leks (1993)
    Springer
    Behavioral ecology and sociobiology 32 (1993), S. 31-39 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We studied 13 ruff leks in a small region on the island of Gotland (Sweden) to investigate the effect of lek size on the costs and benefits of lekking for individual males. Male ruffs occur in two behaviourally and morphologically distinct forms, “independents” (“residents” plus “marginals”) and “satellites”, whose costs and benefits we have assessed separately. These ruff leks had from 1–10 resident (territory-holding) males and were visited daily by satellites, marginals and females from 5–25 May, when most copulations occurred. We used the average number of independent males, counted during censuses taken every 5 min during 2-h observation periods at each lek, as an index of mean lek size. Per independent male, the numbers of both satellites and females increased significantly with mean lek size. Female arrival rate and attendance (total female-minutes) also increased significantly with mean lek size as did the average per capita rate of mating success for resident males (that of satellites was not quite significant). Thus, the dispersion of both of these male categories did not appear to fit an ideal free distribution with respect to mating success. In addition, the number of independent-independent fights per independent and the rate of satellite-resident dyad formation per resident increased significantly with mean lek size. These results suggest that ruffs on larger leks enjoy higher mating success than those on smaller leks but also that costs increase with lek size. We suggest that independent males distribute themselves so as to maximize their own net benefits and that this factor can account for both the occurrence of ruff leks and the variation in their size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172220
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  • 7
    Electronic Resource
    Electronic Resource
    Mate sampling behaviour of black grouse females (Tetrao tetrix) (1995)
    Springer
    Behavioral ecology and sociobiology 37 (1995), S. 209-215 
    Details
    ISSN: 1432-0762
    Keywords: Sexual selection ; Lek ; Mate sampling Female choice ; Tetrao tetrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied female mate sampling behaviour in lekking black grouse (Tetrao tetrix). Females mainly visited males occupying territories in the centre of the lek with relatively large territories. They were also more likely to visit males that had high attendance. The same factors were also correlated with male mating success. A multiple regression model including these factors explained more of the variance in female visits per male (53%) than in mating success (33%). The pattern of female sampling conformed with a pool comparison (best-of-n) tactic. Such a tactic is expected if the costs of sampling are low. Females of high body mass visited more males than lighter females, however, which indicates that females may vary in their search tactics and suggests that there may be search costs. The existence of costs is further suggested by the fact that if the mate from a previous year was still present, females always mated with the same male in the following year. Though search costs were not measured directly, our findings suggest that some costs are negligible (e.g. energetic exhaustion or predation) whereas others (timing of mating) may be more important.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176719
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  • 8
    Electronic Resource
    Electronic Resource
    Mate sampling behaviour of black grouse females (Tetrao tetrix) (1995)
    Springer
    Behavioral ecology and sociobiology 37 (1995), S. 209-215 
    Details
    ISSN: 1432-0762
    Keywords: Key words Sexual selection ; Lek ; Mate sampling ; Female choice ; Tetrao tetrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied female mate sampling behaviour in lekking black grouse (Tetrao tetrix). Females mainly visited males occupying territories in the centre of the lek with relatively large territories. They were also more likely to visit males that had high attendance. The same factors were also correlated with male mating success. A multiple regression model including these factors explained more of the variance in female visits per male (52%) than in mating success (33%). The pattern of female sampling conformed with a pool comparison (best-of-n) tactic. Such a tactic is expected if the costs of sampling are low. Females of high body mass visited more males than lighter females, however, which indicates that females may vary in their search tactics and suggests that there may be search costs. The existence of costs is further suggested by the fact that if the mate from a previous year was still present, females always mated with the same male in the following year. Though search costs were not measured directly, our findings suggest that some costs are negligible (e.g. energetic exhaustion or predation) whereas others (timing of mating) may be more important.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002650050183
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  • 9
    Electronic Resource
    Electronic Resource
    Sexual selection in a monomorphic lek-breeding bird: correlates of male mating success in the great snipe Gallinago media (1987)
    Springer
    Behavioral ecology and sociobiology 21 (1987), S. 211-216 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the lek-breeding great snipe, male morphology, behaviour, and territory features were recorded for individually marked birds on two adjacent leks. Partial correlation sshowed that male mating success, expressed as the number of female solicitations and copulations, was negatively correlated with the distance of a display territory to the lek center and positively correlated with the number of displays per unit time given by a male. No other variables were directly correlated with male matin success. Thus, central males obtain more matings than peripheral males and successful males display more per unit time than do less successful males, independently of position on the lek. Central males were found to be older than peripheral ones and were present more often on the lek. Furthermore, central males had a larger number of white tail feathers, which are usea as visual signals in the displays, but this may be explained by the fact that these males were older. It is suggested that male great snipe are subject to sexual selection mainly in behavioural and vocal cues and that this may explain the absence of size and plumage dimorphism in this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292501
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  • 10
    Electronic Resource
    Electronic Resource
    The effects of parasites on male ornaments and female choice in the lek-breeding black grouse (Tetrao tetrix) (1992)
    Springer
    Behavioral ecology and sociobiology 30 (1992), S. 71-76 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We describe the results of two studies of parasitic infection in the black grouse (Tetrao tetrix). The first deals with our own observations of lekking black grouse in which the parasite levels of two blood parasites, the protozoan Leucocytozoon lovati and microfilaria, probably produced by a nematode worm Splendidofilaria tuvensis, were scored. We also obtained measures of age, survival, number of copulations, body mass and length of the ornamental tail feathers (the lyre) of the lekking males. The second study analysed the data from Lund (1954) which involved eight gut parasites obtained from birds which were killed. In the first study we found higher levels of infection of Leucocytozoon in adults relative to young birds. Parasites had no effect on male survival and there was no correlation in infection between the two types of parasites. Birds infected with microfilaria had shorter tail ornaments. There was no relationship between parasitic infection and mating success. However, the data indicated that such a trend indeed may exist for Leucocytozoon and the most successful males on the leks were less often infected by Leucocytozoon than other males. Results of the second study showed a negative relationship between parasite load (a combined measure of all parasites) and both ornamental tail feather length and body mass. These observations are compatible with, but not conclusive evidence for, the hypothesis of Hamilton and Zuk (1982) on the evolution of secondary sexual characters, where females choose to mate with genetically resistant males which show their resistance by expressing larger and more showy secondary sexual characters. Alternative explanations for the observed patterns are: females avoid infected males for some immediate benefit; and/or parasite loads are indicators of general stress rather than genetical resistance. Under the latter hypothesis females could mate with more vigorous males for reasons unrelated to parasite resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00173942
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