Population Ecology

, Volume 56, Issue 1, pp 119–128 | Cite as

Growth and decline of a penguin colony and the influence on nesting density and reproductive success

  • Richard B. Sherley
  • Peter J. Barham
  • Barbara J. Barham
  • Robert J. M. Crawford
  • Bruce M. Dyer
  • T. Mario Leshoro
  • Azwianewi B. Makhado
  • Leshia Upfold
  • Les G. Underhill
Original article
First Online:
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Accepted:

Abstract

Colonial breeding is characteristic of seabirds but nesting at high density has both advantages and disadvantages and may reduce survival and fecundity. African penguins (Spheniscus demersus) initiated breeding at Robben Island, South Africa in 1983. The breeding population on the island increased in the late 1990s and early 2000s before decreasing rapidly until 2010. Before the number breeding peaked, local nest density in the areas where the colony was initiated plateaued, suggesting that preferred nests sites were mostly occupied, and the area used by breeding birds expanded. However, it did not contract again as the population decreased, so that nesting density varied substantially. Breeding success was related positively to the prey available to the breeding birds and negatively to local nest density, particularly during the chick-rearing period, suggesting a density-dependence operating through social interactions in the colony, possibly exacerbated by poor prey availability when the breeding population was large. Although nest density at Robben Island was not high, nesting burrows, which probably reduce the incidence of aggressive encounters in the colony, are scarce and our results suggest that habitat alteration has modified the strength of density-dependent relationships for African penguins. Gaining a better understanding of how density dependence affects fecundity and population growth rates in colonial breeders is important for informing conservation management of the African penguin and other threatened taxa.

Keywords

Colonial breeding Colony growth Density-dependence Nesting success Population dynamics Seabird conservation 
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Notes

Acknowledgments

The Earthwatch Institute, Leverhulme Trust (PJB, RBS), Bristol Conservation and Science Foundation (RBS), the SeaChange, South Africa-Namibia, and the Rated Researchers Incentive Funding programmes of the National Research Foundation (RJCM, LGU) and our institutions supported this research. The monitoring at Robben Island was conducted as an Earthwatch Institute project on behalf of the Oceans and Coasts branch of the Department of Environmental Affairs (DEA). The research protocol was approved by the animal ethics committees of the University of Bristol and the DEA. Robben Island Museum (RIM), Sabelo Madlala (RIM) and Sue Kuyper provided logistical support. We thank all of those who participated in the Robben Island Earthwatch Project and those who helped with African penguin counts. Fisheries catch data were provided by the Department of Agriculture, Forestry and Fisheries.

Supplementary material

10144_2013_394_MOESM1_ESM.pdf (284 kb)
Supplementary material 1 (PDF 284 kb)

References

  1. Ainley DG (2002) The Adélie penguin: bellwether of climate change. Columbia University Press, New YorkGoogle Scholar
  2. Ashbrook K, Wanless S, Harris MP, Hamer KC (2010) Impacts of poor food availability on positive density dependence in a highly colonial seabird. Proc R Soc B 277:2355–2360PubMedCentralPubMedCrossRefGoogle Scholar
  3. Ballance LT, Ainley DG, Ballard G, Barton G (2009) An energetic correlate between colony size and foraging effort in seabirds, an example of the Adélie penguin Pygoscelis adeliae. J Avian Biol 40:279–288CrossRefGoogle Scholar
  4. Barham PJ, Underhill LG, Crawford RJM, Altwegg R, Leshoro TM, Bolton DA, Dyer BM, Upfold L (2008) The efficacy of hand-rearing penguin chicks: evidence from African penguins (Spheniscus demersus) orphaned in the Treasure oil spill in 2000. Bird Conserv Int 18:144–152Google Scholar
  5. Brown CR, Brown MB (2004) Empirical measurement of parasite transmission between groups in a colonial bird. Ecology 85:1619–1626CrossRefGoogle Scholar
  6. Brunton D (1999) “Optimal” colony size for least terns: an inter-colony study of opposing selective pressures by predators. Condor 101:607–615CrossRefGoogle Scholar
  7. Cordes I, Crawford RJM, Williams AJ, Dyer BM (1999) Decrease of African penguins at the Possession Island group, 1956–1995—contrasting trends for colonial and solitary breeders. Mar Ornithol 27:129–138Google Scholar
  8. Coulson JC (2002) Colonial breeding in seabirds. In: Schreiber EA, Burger J (eds) Biology of marine birds. CRC Press, Boca Raton, pp 217–261Google Scholar
  9. Courchamp F, Clutton-Brock T, Grenfell B (1999) Inverse density dependence and the Allee effect. Trends Ecol Evol 14:405–410PubMedCrossRefGoogle Scholar
  10. Crawford RJM, Boonstra HGvD, Dyer BM, Upfold L (1995) Recolonisation of Robben Island by African penguins, 1983–1992. In: Dann P, Norman I, Reilly PN (eds) The penguins: ecology and management. Surrey Beatty and Sons, NSW Australia, pp 333–363Google Scholar
  11. Crawford RJM, Shannon LJ, Whittington PA, Murison G (2000) Factors influencing growth of the African penguin colony at Boulders, South Africa, 1985–1999. S Afr J Mar Sci 22:111–119CrossRefGoogle Scholar
  12. Crawford RJM, David JHM, Shannon LJ, Kemper J, Klages NTW, Roux J-P, Underhill LG, Ward VL, Williams AJ, Wolfaardt AC (2001) African penguins as predators and prey—coping (or not) with change. S Afr J Mar Sci 23:435–447CrossRefGoogle Scholar
  13. Crawford RJM, Underhill LG, Upfold L, Dyer BM (2007) An altered carrying capacity of the Benguela Upwelling ecosystem for African penguins (Spheniscus demersus). ICES J Mar Sci 64:570–576CrossRefGoogle Scholar
  14. Crawford RJM, Altwegg R, Barham BJ, Barham PJ, Durant JM, Dyer BM, Geldenhuys D, Makhado AB, Pichegru L, Ryan PG, Underhill LG, Upfold L, Visagie J, Waller LJ, Whittington PA (2011) Collapse of South Africa’s penguins in the early 21st century. Afr J Mar Sci 33:139–156CrossRefGoogle Scholar
  15. Croxall JP, Butchart SHM, Lascelles B, Stattersfield J, Sullivan B, Symes A, Taylor P (2012) Seabird conservation status, threats and priority actions: a global assessment. Bird Conserv Int 22:1–34CrossRefGoogle Scholar
  16. Durant JM, Crawford RJM, Wolfaardt AC, Agenbag K, Visagie J, Upfold L, Stenseth NC (2010) Influence of feeding conditions on breeding of African penguins—importance of adequate local food supplies. Mar Ecol Prog Ser 420:263–271CrossRefGoogle Scholar
  17. Eggleton P, Siegfried WR (1979) Displays of the jackass penguin. Ostrich 50:139–167CrossRefGoogle Scholar
  18. Forero MG, Tella JL, Hobson KA, Bertellotti M, Blanco G (2002) Conspecific food competition explains variability in colony size: a test in Magellanic penguins. Ecology 83:3466–3475CrossRefGoogle Scholar
  19. Frost PGH, Siegfried WR, Cooper J (1976) Conservation of the jackass penguin (Spheniscus demersus (L.). Biol Conserv 9:79–99CrossRefGoogle Scholar
  20. Furness RW, Birkhead TR (1984) Seabird colony distributions suggest competition for food supplies during the breeding season. Nature 311:655–656CrossRefGoogle Scholar
  21. Hamer KC, Humphreys EM, Garthe S, Hennicke J, Peters G, Grémillet D, Phillips RA, Harris MP, Wanless S (2007) Annual variation in diets, feeding locations and foraging behaviour of gannets in the North Sea: flexibility, consistency and constraint. Mar Ecol-Prog Ser 338:295–305CrossRefGoogle Scholar
  22. Hoi H, Hoi-Leitner M (1997) An alternative route to coloniality in the bearded tit: females pursue extra-pair fertilisations. Behav Ecol 8:113–119CrossRefGoogle Scholar
  23. Hunt GL, Eppley ZA, Schneider DC (1986) Reproductive performance of seabirds: the importance of population and colony size. Auk 103:306–317Google Scholar
  24. Kramer AM, Dennis B, Liebhold AM, Drake JM (2009) The evidence for Allee effects. Popul Ecol 51:341–354CrossRefGoogle Scholar
  25. Lewis S, Sherratt TN, Hamer KC, Wanless S (2001) Evidence of intra-specific competition for food in a pelagic seabird. Nature 412:816–819PubMedCrossRefGoogle Scholar
  26. Nicoll MAC, Jones CG, Norris K (2003) Declining survival rates in a reintroduced population of the Mauritius kestrel: evidence for non-linear density dependence and environmental stochasticity. J Anim Ecol 72:917–926CrossRefGoogle Scholar
  27. R Development Core Team (2009) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
  28. Ryan PG, Edwards L, Pichegru L (2012) African Penguins Spheniscus demersus, bait balls and the Allee effect. Ardea 100:89–94CrossRefGoogle Scholar
  29. Schuetz J (2011) Reproductive declines in an endangered seabird: cause for concern or signs of conservation success? PLoS ONE 6:e19489PubMedCentralPubMedCrossRefGoogle Scholar
  30. Seddon PJ, van Heezik Y (1991) Effects of hatching order, sibling asymmetries, and nest site on survival analysis of jackass penguin chicks. Auk 108:548–555CrossRefGoogle Scholar
  31. Seddon PJ, van Heezik Y (1993) Chick creching and intraspecific aggression in the jackass penguin. J Field Ornithol 64:90–95Google Scholar
  32. Sherley RB, Barham BJ, Barham PJ, Leshoro TM, Underhill LG (2012) Artificial nests enhance the breeding productivity of African penguins (Spheniscus demersus) on Robben Island, South Africa. Emu 112:97–106CrossRefGoogle Scholar
  33. Sherley RB, Underhill LG, Barham BJ, Barham PJ, Coetzee JC, Crawford RJM, Dyer BM, Leshoro TM, Upfold L (2013) Roles for local and regional prey availability in influencing breeding performance of African penguins Spheniscus demersus. Mar Ecol Prog Ser 473:291–301CrossRefGoogle Scholar
  34. Stokes DL, Boersma PD (2000) Nesting density and reproductive success in a colonial seabird, the Magellanic penguin. Ecology 81:2878–2891CrossRefGoogle Scholar
  35. te Marvelde L, Meininger PL, Flamant R, Dingemanse NJ (2009) Age-specific density-dependent survival in Mediterranean gulls Larus melanocephalus. Ardea 97:305–312CrossRefGoogle Scholar
  36. Tella JL, Forero MG, Bertellotti M, Donazar JA, Blanco G, Ceballos O (2001) Offspring body condition and immunocompetence are negatively affected by high breeding densities in a colonial seabird: a multiscale approach. Proc R Soc B 268:1455–1461PubMedCentralPubMedCrossRefGoogle Scholar
  37. Underhill LG, Sherley RB, Dyer BM, Crawford RJM (2009) Interactions between snakes and seabirds on Robben, Schaapen and Meeuw Islands, Western Cape province, South Africa. Ostrich 80:115–118CrossRefGoogle Scholar
  38. Votier SC, Hatchwell BJ, Mears M, Birkhead TR (2009) Changes in the timing of egg-laying of a colonial seabird in relation to population size and environmental conditions. Mar Ecol Prog Ser 393:225–233CrossRefGoogle Scholar
  39. Weimerskirch H (1990) The influence of age and experience on breeding performance of the Antarctic fulmar Fulmarus glacialoides. J Anim Ecol 59:867–875CrossRefGoogle Scholar
  40. Weimerskirch H, Bertrand S, Silva J, Marques JC, Goya E (2010) Use of social information in seabirds: compass rafts indicates the heading of food patches. PLoS ONE 5:e9928PubMedCentralPubMedCrossRefGoogle Scholar
  41. Wilson RP (1985) Seasonality in diet and breeding success of the jackass penguin Spheniscus demersus. J Ornithol 126:S53–S62CrossRefGoogle Scholar
  42. Yearsley JM, Fletcher D, Hunter C (2003) Sensitivity analysis of equilibrium population size in a density-dependent model for short-tailed shearwaters. Ecol Model 163:119–129CrossRefGoogle Scholar

Copyright information

© The Society of Population Ecology and Springer Japan 2013

Authors and Affiliations

  • Richard B. Sherley
    • 1
    • 2
  • Peter J. Barham
    • 1
    • 3
  • Barbara J. Barham
    • 4
  • Robert J. M. Crawford
    • 1
    • 5
  • Bruce M. Dyer
    • 5
  • T. Mario Leshoro
    • 6
  • Azwianewi B. Makhado
    • 5
  • Leshia Upfold
    • 5
  • Les G. Underhill
    • 1
    • 2
  1. 1.Animal Demography Unit, Department of Biological SciencesUniversity of Cape TownRondeboschSouth Africa
  2. 2.Marine Research Institute, University of Cape TownRondeboschSouth Africa
  3. 3.H H Wills Physics LaboratoryUniversity of BristolBristolUK
  4. 4.Penguin DatasystemsBristolUK
  5. 5.Oceans and Coasts, Department of Environmental AffairsCape TownSouth Africa
  6. 6.Robben Island MuseumRobben IslandSouth Africa

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