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.

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.

.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.

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).

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.

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

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

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

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

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.

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

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, r

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.

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