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The comparative effects of small geographic range and population decline on the adult sex ratio of threatened bird species

  • J. C. VENABLES (a1) and M. de L. BROOKE (a1)

Summary

Although the factors associated with adult sex ratio (ASR) skew in threatened species are rarely identified, ASRs of threatened species appear to be more male-skewed with increasing severity of threat. In this study we investigate whether the ASRs of species classified as threatened because of decline are significantly different from those threatened because of small range. Despite previous studies suggesting an association between male-skewed ASRs and population decline, our results show that ASRs may be more male-skewed in species classified as threatened because of small range. Although selection would be expected to purge dispersal genotypes from isolated populations, our finding could result from an imbalance between immigration and emigration rates of species with small ranges. Future research should examine rates of emigration and immigration in species with small global ranges.

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Corresponding author

*Author for correspondence; email: m.brooke@zoo.cam.ac.uk

References

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Anderson, D. J., Porter, E. T. and Ferree, E. D. (2004) Non-breeding Nazca boobies (Sula granti) show social and sexual interest in chicks: behavioural and ecological aspects. Behaviour 141: 959977.
Barton, K. (2012) Package ‘MuMIn’. [online] Available at: < http://cran.r-project.org/web/packages/MuMIn/MuMIn.pdf> [Accessed 08 July 2012].
Brooke, M. de, L., Flower, T. P., Campbell, E. M., Mainwaring, M. C., Davies, S. and Welbergen, J. A. (2012) Rainfall-related population growth and sex ratio change in the Critically Endangered Raso lark Alauda razae . Anim. Conserv. 16: 466471.
Burnham, K. P. and Anderson, D. R. (2002) Model selection and multimodel inference: a practical information theoretic approach. 2 nd edition. New York: Springer-Verlag.
Cooper, C. B. and Walters, J. R. (2002) Experimental evidence of disrupted dispersal causing decline of an Australian passerine in fragmented habitat. Conserv. Biol. 16: 471478.
Dale, S. (2001) Female-biased dispersal, low female recruitment, unpaired males, and the extinction of small and isolated bird populations. Oikos 92: 344356.
Donald, P. F. (2007) Adult sex ratios in wild bird populations. Ibis 149: 671692.
Eaton, M. A., Marshall, K. B. and Gregory, R. D. (2007) Status of capercaillie Tetrao urogallus in Scotland during winter 2003/4. Bird Study 54: 145153.
Gerlach, J. and Le Maitre, S. (2001) Sex ratio variation in small island populations of an endangered bird, the Seychelles Magpie Robin, Copsychus sechellarum. Ostrich 72: 114117.
Grüebler, M. U., Schuler, H., Müller, M., Spaar, R., Horch, P. and Naef-Daenzer, B. (2008) Female biased mortality caused by anthropogenic nest loss contributes to population decline and adult sex ratio of a meadow bird. Biol. Conserv. 141: 30403049.
Helle, P., Kurki, S. and Linden, H. (1999) Changes in the sex ratio of the Finnish capercaillie Tetrao urogallus population. Wildlife Biol. 5: 2531.
Hui, C., Roura-Pascual, N., Brotons, L., Robinson, R. A. and Evans, K. L. (2012) Flexible dispersal strategies in native and non-native ranges: environmental quality and the ‘good-stay, bad-disperse’ rule. Ecography 35: 19.
IUCN (2001) IUCN Red List categories and criteria: Version 3.1. Gland, Switzerland and Cambridge, UK: IUCN Species Survival Commission. IUCN.
Lee, P. L. M., Brain, P. F., Forman, D. W., Bradbury, R. B. and Griffiths, R. (2002) Sex and death: CHD1Z associated with high mortality in moorhens. Evolution 56: 25482553.
Lehikoinen, A., Christensen, T. K., Öst, M., Kilpi, M., Saurola, P. and Vattulainen, A. (2008) Large-scale change in the sex ratio of a declining eider Somateria mollissima population. Wildlife Biol. 14: 288301.
Li, W. M., Feng, Y. P., Zhao, R. X., Fan, Y. Z., Affara, N. A., Wu, J. J, Fang, J., Tong, Q., Wang, C. and Zhang, S. J. (2008) Sex ratio bias in early-dead embryos of chickens collected during the first week of incubation. Poultry Sci. 87: 22312233.
Liker, A. and Székely, T. (2005) Mortality costs of sexual selection and parental care in natural populations of birds. Evolution 59: 890897.
Matthysen, E., Adriaensen, F. and Dhondt, A. (1995) Dispersal distances of nuthatches, Sitta europaea, in a highly fragmented forest habitat. Oikos 72: 375381.
Schaub, M., Reichlin, T. S., Abadi, F., Kéry, M., Jenni, L. and Arlettaz, R. (2012) The demographic drivers of local population dynamics in two rare migratory birds. Oecologia 168: 97108.
Schtickzelle, N. and Baguette, M. (2003) Behavioural responses to habitat patch boundaries restrict dispersal and generate emigration-patch area relationships in fragmented landscapes. J. Anim. Ecol. 72: 533545.
Schtickzelle, N., Mennechez, G. and Baguette, M. (2006) Dispersal depression with habitat fragmentation in the bog fritillary butterfly. Ecology 87: 10571065.
Smith, G. R. and Iverson, J. B. (2006) Changes in sex ratio over time in the endangered iguana Cyclura chychlura inornata . Can. J. Zool. 84: 15221527.
Steifetten, O. and Dale, S. (2006) Viability of an endangered population of ortolan buntings: The effect of a skewed operational sex ratio. Biol. Conserv. 132: 8897.
Taylor, S. S., Leonard, M. L. and Boness, D. J. (2001) Aggressive nest intrusions by male Humboldt penguins. Condor 103: 162165.
Travis, J. M. J. and Dytham, C. (1999) Habitat persistence, habitat availability and the evolution of dispersal. Proc. R. Soc. Lond. B 266: 723728.
Venables, J. C. (2012) Factors affecting adult sex ratios in bird populations. PhD thesis, University of Cambridge, UK.
Ward, M. P. (2005) The role of immigration in the decline of an isolated migratory bird population. Conserv. Biol. 19: 15281536.
Weatherhead, P. J. and Forbes, M. R. L. (1994) Natal philopatry in passerine birds: genetic or ecological influences? Behav. Ecol. 5: 426433.
Wilkinson, N. I., Langston, R. H. W., Gregory, R. D., Gibbons, D. W. and Marquiss, M. (2002) Capercaillie Tetrao urogallus abundance and habitat use in Scotland, in winter 1998–99. Bird Study 49: 177185.
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