Journal für Ornithologie

, Volume 144, Issue 3, pp 307–316 | Cite as

Exploitation of resources modulates stopover behaviour of passerine migrants

Article

Summary

The seasonal variation in the supply of ripe Elderberries (Sambucus nigra) on the offshore island of Helgoland (North Sea) was examined from the point of view of the effect of food supply and exploitation on the stopover behaviour of migrating passerines. Elderberries were completely exploited by birds by mid October, three weeks earlier than the last berries disappeared from exclosures. In five out of seven frugivorous passerine species the percentage of trapped birds settling (i. e. recaptured on days subsequent to initial capture) was significantly higher during the period of high availability of ripe Elderberries (early September to early October) than it was earlier (berries still unripe) and later (berries exhausted). No such pattern was observed in fuel deposition rates because rates of body mass change in recaptures differed between periods in only one out of five species. Therefore, in conjunction with the shortage of alternative food, berry supply had an impact on the stopover decision, but did not affect the refuelling itself. The energy demand of migrants as calculated from the number of birds present could not be covered by Elderberries from mid October onwards. Hence, exploitation by earlier migrants reduced the carrying capacity of the stopover site for later migrants, especially when high bird densities were involved. Continent-wide patterns of fuel deposition may have evolved in order to avoid such shortages of food for refuelling just before the crossing of ecological barriers. Passerine migrants would benefit from dispersed resources which allow the avoidance of crowding and exhaustion of supply.

Keywords

stopover ecology passerine birds frugivory Black Elder Sambucus nigra 

Ausbeutung des Nahrungsangebotes beeinflusst das Rastverhalten ziehender Singvögel

Zusammenfassung

Die jahreszeitliche Variation im Angebot an Holunderbeeren (Sambucus nigra) auf der Insel Helgoland wurde gewählt, um die Effekte des Nahrungsangebots und dessen Ausbeutung auf das Rastverhalten ziehender Singvögel zu untersuchen. Holunderbeeren wurden von Vögeln bis Mitte Oktober vollständig ausgebeutet, so dass drei Wochen früher als in Exklusionsversuchen keine Holunderbeeren mehr vorhanden waren. In fünf von sieben untersuchten Singvogelarten war die Wiederfangrate von im Fanggarten beringten frugivoren Vögeln zur Zeit der Holunderreife (Anfang September bis Anfang Oktober) signifikant höher als in Zeiten davor (Beeren noch unreif) bzw. danach (Beeren ausgebeutet). In der Nährstoffdepositionsrate ließ sich beim Vergleich dieser Zeiträume allerdings nur bei einer von fünf Arten ein signifikanter Unterschied finden. Im Einklang mit dem Fehlen quantitativ bedeutender Alternativnahrung hatte das Nahrungsangebot also einen Einfluss auf die Entscheidung über Rast oder Abzug, beeinflusste aber offenbar nicht die Nährstoffdeposition selbst. Der Energiebedarf auf Helgoland beobachteter frugivorer Zugvögel (16 Arten) konnte ab Mitte Oktober nicht mehr durch Holunderbeeren gedeckt werden. Die Ausbeutung durch früher ziehende Vögel hat demnach die Umweltkapazität des Rastgebietes für später ziehende Vogel erheblich reduziert, besonders für Tage mit hoher Vogeldichte. Kontinentweite Muster der Nährstoffdeposition haben sich möglicherweise entwickelt, um solche Engpässe vor der Überquerung von ökologischen Barrieren zu vermeiden. Ubertragen auf isolierte Habitate zeigen die Ergebnisse von Helgoland, dass ziehende Singvögel von weit verteilten Ressourcen, die hohe Dichte und starke Ausbeutung verhindem, profitieren können.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Alerstam, T. (1978): Reoriented bird migration in coastal areas: dispersal to suitable resting grounds? Oikos 30: 405–408.Google Scholar
  2. Alerstam, T. (1990): Bird migration. Cambridge.Google Scholar
  3. Alerstam, T., Gudmundsson, G. A. & Johannesson, K. (1992): Resources for long distance migration: intertidal exploitation ofLittorina andMytilus by knotsCalidris canutus in Iceland. Oikos 65: 179–189.Google Scholar
  4. Alerstam, T. & Lindstrom, A. (1990): Optimal bird migration: the relative importance of time, energy, and safety. In: E. Gwinner (Ed.): Bird migration: physiology and ecophysiology: 331–351. Berlin.Google Scholar
  5. Bairlein, F. (1985): Body weight and fat deposition of Palaearctic passerine migrants in the central Sahara. Oecologia 66: 141–146.CrossRefGoogle Scholar
  6. Bairlein, F. (1991): Body mass of Garden Warblers (Sylvia borin) on migration: a review of field data. Vogelwarte 36:48–61.Google Scholar
  7. Bairlein, F. (1999): Energy and nutrient utilisation efficiencies in birds: a review. Proc. 22 Int. Ornithol. Congr. Durban: 2221–2246.Google Scholar
  8. Bairlein, F. (2002): How to get fat: nutritional mechanisms of seasonal fat accumulation in migratory songbirds. Naturwiss. 89: 1–10.PubMedCrossRefGoogle Scholar
  9. Bairlein, F. & Simons, D. (1995): Nutritional adaptations in migrating birds. Israel J. Zool. 41:357–367.Google Scholar
  10. Bibby, C. J. & Green, R. E. (1981): Autumn migration strategies of Reed and Sedge Warblers. Ornis Scand. 12: 1–12.Google Scholar
  11. Biebach, H. (1995): Stopover of migrants flying across the Mediterranean Sea and the Sahara. Israel J. Zool. 41: 387–392.Google Scholar
  12. Boddy, M. (1991): Some aspects of frugivory by bird populations using coastal dune scrub in Lincolnshire. Bird Study 38: 188–199.CrossRefGoogle Scholar
  13. Bruderer, B. & Jenni, L. (1988): Strategies of bird migration in the area of the Alps. Acta XIX Congr. Int. Ornithol.: 2150–2161.Google Scholar
  14. Delingat, J. & Dierschke, V. (2000): Habitat utilization by Northern Wheatears (Oenanthe oenanthe) stopping over on an offshore island during spring migration. Vogelwarte 40:271–278.Google Scholar
  15. Dierschke, V. & Bindrich, F. (2001): Body condition of migrant passerines crossing a small ecological barrier. Vogelwarte 41: 119–132.Google Scholar
  16. Dolnik, V. R. (1990): Bird migration across arid and mountainous regions of middle Asia and Kazakhstan. In: E. Gwinner (Ed.): Bird migration: physiology and ecophysiology: 368–386. Berlin.Google Scholar
  17. Hansson, M. & Pettersson, J. (1989): Competition and fat deposition in Goldcrests (Regulus regulus) at a migration stop-over site. Vogelwarte 35: 21–31.Google Scholar
  18. Hedenström, A. & Alerstam, T. (1997): Optimal fuel loads in migratory birds: distinguishing between time and energy minimization. J. theor. Biol. 189: 227–234.PubMedCrossRefGoogle Scholar
  19. Hutto, R. L. (1985): Habitat selection by nonbreeding, migratory land birds. In: M. L. Cody (Ed.): Habitat selection in birds: 455–476. New York.Google Scholar
  20. Jenni-Eiermann, S. & Jenni, L. (1999): Habitat utilisation and energy storage in passerine birds during migratory stopover. Proc. 22 Int. Ornithol. Congr. Durban: 803–818.Google Scholar
  21. Kelly, J. F., DeLay, L. S. & Finch, D. M. (2002): Density-dependent mass gain by Wilson's Warblers during stopover. Auk 119: 210–213.CrossRefGoogle Scholar
  22. Kroll, H. (1972): Zur Nahrungsökologie der Gartengrasmücke (Sylvia borin) beim Herbstzug 1969 auf Helgoland. Vogelwarte 26: 280–285.Google Scholar
  23. Lindström, Å. & Alerstam, T. (1986): The adaptive significance of reoriented migration of chaffinchesFringilla coelebs and bramblingsF. montifringilla during autumn in southern Sweden. Behav. Ecol. Sociobiol. 19: 417–424.CrossRefGoogle Scholar
  24. Lindström, Å. & Kvist, A. (1995): Maximum energy intake rate is proportional to basal metabolic rate in passerine birds. Proc. R. Soc. Lond. B 261: 337–343.Google Scholar
  25. Martin, T. E. (1980): Diversity and abundance of spring migratory birds using habitat islands on the Great Plains. Condor 82: 430–439.Google Scholar
  26. Mehlum, F. (1983): Weight changes in migrating RobinsErithacus rubecula during stop-over at the island of Store Færder, Outer Oslofjord, Norway. Fauna norv. Ser. C, Cinclus 6: 57–61.Google Scholar
  27. Moore, F. & Kerlinger, P. (1987): Stopover and fat deposition by North American wood-warblers (Parulinae) following spring migration over the Gulf of Mexico. Oecologia 74: 47–54.CrossRefGoogle Scholar
  28. Moore, F. R., Kerlinger, P. & Simons, T. R. (1990): Stopover on a Gulf coast barrier island by spring trans-Gulf migrants. Wilson Bull. 102: 487–500.Google Scholar
  29. Moore, F. R. & Yong, W. (1991): Evidence of food-based competition among passerine migrants during stopover. Behav. Ecol. Sociobiol. 28: 85–90.CrossRefGoogle Scholar
  30. Moritz, D. (1982): Langfristige Bestandsschwankungen ausgewählter Passeres nach Fangergebnissen auf Helgoland. Seevögel 3, Suppl.: 13–24.Google Scholar
  31. Ottich, I. (2002): Nahrungsangebot und -nutzung durch fmgivore Zugvögel auf Helgoland. Thesis Univ. Frankfurt am Main.Google Scholar
  32. Petersen, F. D. (1972): Weight-changes at Hesselø in night migrating passerines due to time of day, season and environmental factors. Dansk Ornithol. Foren. Tidsskr. 66: 97–107.Google Scholar
  33. Schaub, M. & Jenni, L. (2000a): Fuel deposition of three passerine bird species along the migration route. Oecologia 122: 306–317.CrossRefGoogle Scholar
  34. Schaub, M. & Jenni, L. (2000b): Body mass of six long-distance migrant passerine species along the autumn migration route. J. Ornithol. 141: 441–460.Google Scholar
  35. Schrey, E. (1981): Nahrungsökologische Untersuchungen an Helgoländer Staren (Sturnus vulgaris). Vogelwelt 102: 219–232.Google Scholar
  36. Simons, D. & Bairlein, F. (1990): Neue Aspekte zur zugzeitlichen Frugivorie der Gartengrasmücke (Sylvia borin). J. Ornithol. 131: 381–401.CrossRefGoogle Scholar
  37. Simons, T. R., Pearson, S. M. & Moore, F. R. (2000): Application of spatial models to the stopover ecology of trans-Gulf migrants. Stud. Avian Biol. 20: 4–14.Google Scholar
  38. Snow, B. & Snow, D. (1988): Birds and berries. Calton.Google Scholar
  39. Spina, F. & Bezzi, E. M. (1990): Autumn migration and orientation of the Sedge Warbler (Acrocephalus schoenobaenus) in northern Italy. J. Ornithol. 131: 429–438.CrossRefGoogle Scholar
  40. Weigold, H. (1930): Der Vogelzug auf Helgoland graphisch dargestellt. Berlin.Google Scholar
  41. Wiedner, D.S., Kerlinger, P., Sibley, D. A., Holt, P., Hough, J. & Crossley, R. (1992): Visible morning flight of Neotropical landbird migrants at Cape May, New Jersey. Auk 109: 500–510.Google Scholar

Copyright information

© Deutsche Ornithologen-Gesellschaft/Blackwell Verlag 2003

Authors and Affiliations

  1. 1.Institut für Vogelforschung „Vogelwarte Helgoland“, Inselstation HelgolandHelgolandGermany

Personalised recommendations