waddensea sexes

Fig. 1. Frequency distribution of morphologically sexed males (n = c1519, white columns) and females (n = c1889, black columns) in the German Waddensea 10.5 - 31.5, 1979 to 1994. Both sexes from base line, interpolated medians shown with arrows. Material: fig. 6, page 86 in Rösner 1997.







bill ln scale

Fig. 2. Male and female bill-length distributions, the Waddensea. The same material as in fig. 1, but ln scale and female distribution inverted. Calculated from data in fig. 6, page 86 in Rösner 1997 (Fig. 1 of this paper). The accuracy of graphically determined medians etc. depends on pixel size, it is > 0.1.









relative m/f

.Fig. 3. Percentage of Waddensea males and females (filled squares; n=3408) on eighteen intervals from 28 to 39 mm (28 - 28.9, 29 - 29.9, 30 - 30.4 etc. 36.5 - 36.9, 37 - 37.9. 38 - 38.9 mm) and Falsterbo males and females (open squares; n=326) on nine intervals from 29 to 38 mm. 50 : 50 ratios, Waddensea material from Fig. 6, page 86 in Rösner 1997 (Fig. 1 of this paper), Falsterbo material July - August.









sex ratio

Fig. 4. Ratio between the frequency of bill lengths 30 - 32.9 mm and 34.5 - 37.4 mm with sex ratio male : female changing from 20 : 80 to 80 : 20. Material from fig. 6, page 86 in Rösner 1997 (Fig. 1 of this paper).









sex ratio in adults

Fig. 5. Approximate frequency distribution of males (n = 518, white columns) and females (n = 281, black columns) from the Falsterbo peninsula 12.7 - 31.8 1995 - 2002. Both sexes from the base line, true sample size in each interval. Sex ratio estimated from Fig. 4, distributions recreated with the distributions of Fig. 1 as prototype. Interpolated medians shown with arrows.









juv:july-19nov

Fig. 6. Bill length distribution in juveniles from the Falsterbo peninsula, 12.7 - 19.11. n=2117. Mean value shown with arrow.










winterbills/falsterbobeforeny

Fig. 7. Bill length distribution from Falsterbo peninsula, all ages, 20.11 - 31.12. n=234. Mean value shown with arrow.










winterbills/barseback

Fig. 8. Bill length distribution from Barsebäck, all ages, 26.12 - 3.1. n=122. Mean value shown with arrow.










winterbills/falsterboafterny

Fig. 9. Bill length distribution from Falsterbo peninsula, all ages, 1.1 - 28.2. n=96. Mean value shown with arrow.










yamalbothsexes

Fig. 10. Bill length distributions of morphologically sexed breeding Dunlin from Yamal Peninsula, summer 1993, measurements by Henning Behmann and Maciej Gromadzki (n = 52 + 52). Both sexes from base line, mean values shown with arrows.










yamalm/fchoice

Fig. 11. Disassortive mating of 22 pairs of Dunlin from Yaibari area, Yamal peninsula, 1993, data by H. Behmann.










yamalm/fdistance

Fig. 12. Difference between male and female bill-length in the pairings of Fig. 11 as a function of male bill-length. Regression: DIFF = -1.18 BL + 39.7, r2 = 0.70, F1,19 = 43.7, p < 0.001










model distributions

Fig. 13. Two model distributions, in "A" the left one is leptokurtic (kurtosis = 0.17), the right one platykurtic (kurtosis = -0.27). In "A" the left one has skewness 0.32, the right one 0, in "B" the left one has skewness 0.58, the right one -0.49. The numbers show the rating ("bill-length") of each cell.










yamalm<blink>/fchoice

Fig. 14. Disassortive mating of the distributions in Fig. 13: the most short-billed cell to the left is mated to the most long-billed cell at hand to the right, or vice versa. The distance between left cell and right cell ratings shown as a function of left cell rating. The points shown refer to alternative A.






Last changed 25.3.03