Advertisement

Journal of Ornithology

, Volume 155, Issue 1, pp 53–63 | Cite as

Population density and use of grasslands by female Little Bustards during lek attendance, nesting and brood-rearing

  • João Paulo SilvaEmail author
  • Beatriz Estanque
  • Francisco Moreira
  • Jorge Manuel Palmeirim
Original Article

Abstract

The Little Bustard (Tetrax tetrax) is one of Europe’s most threatened birds, and depends mostly on extensive agricultural and pastoral schemes for survival. Due to the female’s secretive behaviour, information concerning female breeding ecology is scarce and restricted to sites with some level of agricultural intensification. Consequently, most advice for improving the habitat for this species is based on male habitat needs alone. The breeding season encompasses three distinct biological phases for females—visiting lekking males, nesting, and brood-rearing—which are likely to result in different habitat requirements. In northern Alentejo (Portugal), we studied how female densities vary during the breeding season and analysed their habitat preferences at different scales during the three phases. Both female and male density varied during the season. Local and regional female densities of 16 and 7.6 females/100 ha, respectively, are among the highest ever recorded for the species. The results of a binary GLM suggest a greater probability for the occurrence of nests in larger grassland fields with a vegetation height under 42 cm. Nests were also located preferentially in the proximity of displaying males. Female micro habitat requirements varied significantly throughout the breeding season. Vegetation heterogeneity in larger grassland fields is likely to play an important role in providing adequate habitat for females throughout the whole breeding season. Large grassland fields should, therefore, constitute a management priority in key breeding sites for the species.

Keywords

Tetrax tetrax Habitat Microhabitat Field size Vegetation structure Management 

Zusammenfassung

Bestandsdichte und die Nutzung von Grünland durch Zwergtrappen Weibchen während der Anwesenheit in Balzarenen sowie während der Nist- und Aufzuchtphase

Die Zwergtrappe (Tetrax tetrax) ist eine der am stärksten bedrohten Vogelarten in Europa. Das Überleben der Art hängt größtenteils von extensiven Bewirtschaftungsprogrammen landwirtschaftlich genutzter Flächen ab. Aufgrund des heimlichen Verhaltens der Weibchen sind Informationen zur Brutökologie spärlich und beschränken sich auf landwirtschaftliche Gebiete mit einem gewissen Intensivierungsgrad. Infolgedessen basieren die meisten der Empfehlungen hinsichtlich Lebensraumverbesserungen für diese Art allein auf Kenntnissen zu Habitatanforderungen der Männchen. Für die Weibchen umfasst die Brutsaison drei unterschiedliche biologische Phasen – Besuch der Balzarenen der Männchen, Nistperiode und Jungenaufzucht. In diesen Phasen haben die Weibchen wahrscheinlich unterschiedliche Ansprüche an das jeweilige Habitat. Im nördlichen Teil der Region Alentejo (Portugal) untersuchten wir, wie die Dichte der Weibchen während der Brutsaison variiert und analysierten ihre Habitatpräferenzen in verschiedenen Maßstäben während der drei Phasen. Sowohl die Dichte der Weibchen als auch die der Männchen schwankte während der Brutsaison. Lokale und regionale Weibchendichten von 16 bzw. 7,6 Weibchen/100 ha sind die höchsten, die jemals für diese Art beobachtet wurden. Die Ergebnisse eines binären Generalisierten Linearen Modelles (GLM) zeigen eine größere Wahrscheinlichkeit für das Vorkommen von Nestern in größeren Grünlandflächen mit einer Vegetationshöhe von unter 34 cm. Die Nester lagen zudem bevorzugt in der Nähe von balzenden Männchen. Die Mikrohabitatansprüche der Weibchen variierten signifikant während der Brutsaison. Die Heterogenität der Vegetation in größeren Grünlandbereichen spielt wahrscheinlich eine entscheidende Rolle hinsichtlich des Angebots an adäquaten Habitaten für die Weibchen während der gesamten Brutzeit. In den Kernbrutgebieten der Zwergtrappe sollten daher dem Schutz und Management großräumiger Grünlandgebiete eine hohe Priorität eingeräumt werden.

Notes

Acknowledgments

We are thankful to the farmers who granted us access to their land and to the volunteers who kindly assisted us during field work: Joana Galego, Ana Pereira, Anais André, Elisabete Freitas, Leonor Martins, Luís Venâncio, Miguel Saragoça, Nigel Collar, Nuno Faria, Pedro Pereira, Raquel Pingo, Vanessa Gil. JP Silva was funded by grants SFRH/BD/28805/2006 and SFRH/BPD/72311/2010 from Fundação para a Ciência e Tecnologia.

References

  1. Bergerud AT, Gratson MW (1988) Survival and breeding strategies of grouse. In: Bergerud AT, Gratson MW (eds) Adaptive strategies and population ecology of northern grouse. Wildlife Management Institute, Washington, D.C., USA, pp 498–577Google Scholar
  2. BirdLife International (2004) Birds in Europe: population estimates, trends and conservation status. BirdLife Conservation Series no 10. BirdLife International, CambridgeGoogle Scholar
  3. BirdLife International (2008) Tetrax tetrax. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. http://www.iucnredlist.org
  4. Burnham KP, Anderson DR (2002) Model selection and multimodel inference: a practical information-theoretic approach. Springer, New YorkGoogle Scholar
  5. Campos B, López M (1996) Densidad y selección de hábitat del Sisón (Tetrax tetrax) en el Campo de Montiel (Castilla-La Mancha), España. In: Fernández Gutiérrez J, Sanz-Zuasti J (eds) Conservación de Las Aves Esteparias y su Hábitat. Junta de Castilla y León, Valladolid, pp 201–208Google Scholar
  6. Cramp S, Simmons KEL (1980) The Birds of the Western Paleartic. Oxford University Press, LondonGoogle Scholar
  7. Davis SK (2004) Area sensitivity in grassland passerines: effects of patch size, patch shape, and vegetation structure on bird abundance and occurrence in southern Saskatchewan. Auk 124:1130–1145Google Scholar
  8. Del Hoyo J, Elliot A, Sargatal J (1996) Handbook of the birds of the world. Lynx, BarcelonaGoogle Scholar
  9. Delgado A, Moreira F (2000) Bird assemblages of an Iberian cereal steppe. Agric Ecosyst Environ 78:65–76CrossRefGoogle Scholar
  10. Delgado A, Moreira F (2010) Between-year variations in Little Bustard Tetrax tetrax population densities are influenced by agricultural intensification and rainfall. Ibis 152:633–642CrossRefGoogle Scholar
  11. Faria N, Rabaça JE, Morales MB (2012) The importance of grazing regime in the provision of breeding habitat for grassland birds: the case of the endangered little bustard (Tetrax tetrax). J Nat Conserv 20:211–218CrossRefGoogle Scholar
  12. García J, Suárez-Seoane S, Miguélez D, Osborne PE, Zumalacárregui C (2007) Spatial analysis of habitat quality in a fragmented population of little bustard (Tetrax tetrax): implications for conservation. Biol Conserv 137:45–56CrossRefGoogle Scholar
  13. Goriup P (1994) Little Bustard Tetrax tetrax. In: Tucker GM, Heath MF (eds) Birds in Europe: their conservation status. BirdLife International, Cambridge, pp 236–237Google Scholar
  14. Höglund J, Alatalo RV (1995) Leks. Princeton University Press, NewJerseyGoogle Scholar
  15. Hosmer DW, Lemeshow S (2000) Applied logistic regression. Wiley, New YorkCrossRefGoogle Scholar
  16. Iñigo A, Borov B (2010) Action plan for the little bustard Tetrax tetrax in the European Union. SEO|BirdLife and BirdLife International for the European Commission. http://ec.europa.eu/environment/nature/conservation/wildbirds/action_plans/docs/tetrax_tetrax.pdf
  17. Jiguet F (2002) Arthropods in diet of Little Bustards Tetrax tetrax during the breeding season in western France. Bird Study 49:105–109CrossRefGoogle Scholar
  18. Jiguet F, Bretagnolle V (2001) Courtship behaviour in a lekking species: individual variations and settlement tactics in male little bustard. Behav Process 55:107–118CrossRefGoogle Scholar
  19. Jiguet F, Bretagnolle V (2006) Manipulating lek size and composition using decoys: an experimental investigation of lek evolution models. Am Nat 168:758–768PubMedCrossRefGoogle Scholar
  20. Jiguet F, Wolff A (2000) Determiner l’âge et le sexe des outardes canepetières Tetrax tetrax a l’automne. Ornithos 7:30–35Google Scholar
  21. Jiguet F, Arroyo B, Bretagnolle V (2000) Lek mating systems: a case study in the little bustard Tetrax tetrax. Behav Process 51:63–82CrossRefGoogle Scholar
  22. Jiguet F, Jaulin S, Arroyo B (2002) Resource defence on exploded leks: do male little bustards, T. tetrax, control resources for females? Anim Behav 63:899–905CrossRefGoogle Scholar
  23. Lapiedra O, Ponjoan A, Gamero A, Bota G, Mañosa S (2011) Brood ranging behaviour and breeding success of the threatened little bustard in an intensified farmland área. Biol Conserv 144:2882–2890CrossRefGoogle Scholar
  24. Martínez C (1994) Habitat selection by the Little Bustard Tetrax tetrax in cultivated areas of Central Spain. Biol Conserv 67:125–128CrossRefGoogle Scholar
  25. Martínez C (1998) Selección de Microhábitat del Sisón Común Tetrax tetrax Durante la Estación Reproductora. Ardeola 45:73–76Google Scholar
  26. Martínez C, Tapia GG (2002) Density of the Little Bustard Tetrax tetrax in relation to agricultural intensification in Central Spain. Ardeola 49:301–304Google Scholar
  27. Morales MB, García JT, Arroyo B (2005) Can landscape composition changes predict spatial and annual variation of little bustard male abundance? Anim Conserv 8:167–174CrossRefGoogle Scholar
  28. Morales MB, Suárez F, García de La Morena E (2006) Réponses des oiseaux de steppe aux différents niveaux de mise en culture et d’intensification du paysage agricole: une analyse comparative de leurs effets sur la densité de population et la sélection de l’habitat chez l’outarde canepetiere Tetrax tetrax et l’outarde barbue Otis tarda. Rev Ecol (Terre et Vie) 61:261–270Google Scholar
  29. Morales MB, Traba J, Delgado MP, García de la Morena E (2008) Sexual differences in microhabitat selection of breeding little bustards Tetrax tetrax: ecological segregation based on vegetation structure. Acta Oecol 34:345–353CrossRefGoogle Scholar
  30. Moreira F (1999) Relationships between vegetation structure and breeding bird densities in fallow cereal steppes in Castro Verde, Portugal. Bird Study 46:309–318CrossRefGoogle Scholar
  31. Moreira F, Silva JP, Estanque B, Lecoq M, Palmeirim JM, Pinto M, Leitão D, Alonso I, Pedroso R, Santos E, Catry T, Silva P, Henriques I, Delgado A (2012) Mosaic-level inference of the impact of land cover changes in agricultural landscapes on biodiversity: a case-study with a threatened grassland bird. PLoS ONE 7:1–10Google Scholar
  32. Osborne PE, Suárez-Seoane S (2007) Identifying core areas in a species’ range using temporal suitability analysis: an example using little bustards Tetrax tetrax L. in Spain. Biodivers Conserv 16:3505–3518CrossRefGoogle Scholar
  33. Phillips JB (1990) Lek behaviour in birds: do displaying males reduce nest predation? Anim Behav 39:555–565CrossRefGoogle Scholar
  34. Rivas-Martínez S (1981) Les étages bioclimatiques de la végétation de la Péninsule Ibérique. An Jard Bot Madrid 37:251–268Google Scholar
  35. Schulz H (1985a) A review of the world status and breeding distribution of the Little Bustard. Bustard Stud 2:131–152Google Scholar
  36. Schulz H (1985b) Grundlagenforschung zur Biologie der Zwergtrappe Tetrax tetrax. PhD thesis. Staatlichen Naturhistorischen Museum, BraunschweigGoogle Scholar
  37. Schulz H (1987) Biologie et protection de L’Outarde Canepetiere Tetrax tetrax. Faune Provence 8:54–78Google Scholar
  38. Silva JP, Pinto M (2006) Final report of Action 2 of the Project LIFE02NAT/P/8476: Conservation of the little bustard in Alentejo. Institute for Nature Conservation. http://portal.icnb.pt/NR/rdonlyres/783CA43B-7C0E-4FA4-8286-F4EB120C4A49/0/Life_SISAO.pdf
  39. Silva JP, Pinto M, Palmeirim JM (2004) Managing landscapes for little bustard Tetrax tetrax: lessons from the study of winter habitat selection. Biol Conserv 117:521–528CrossRefGoogle Scholar
  40. Silva JP, Faria N, Catry T (2007) Summer habitat selection and abundance of the threatened little bustard Tetrax tetrax in Iberian agricultural landscapes. Biol Conserv 139:186–194CrossRefGoogle Scholar
  41. Silva JP, Palmeirim JM, Moreira F (2010) Higher breeding densities of the threatened little bustard Tetrax tetrax occur in larger grassland fields: implications for conservation. Biol Conserv 143:2553–2558CrossRefGoogle Scholar
  42. Sokal RR, Rohlf FJ (1995) Biometry: the principles and practice of statistics in biological research, 3rd edn. W. H. Freeman and Company, New YorkGoogle Scholar
  43. Suárez F, Naveso MA, De Juana E (1997) Farming in the drylands of Spain: birds of the pseudosteppes. In: Pain DJ, Pienkowski MW (eds) Farming and birds in Europe. The Common Agricultural Policy and its implication for bird conservation. Academic Press, London, pp 297–330Google Scholar
  44. Suárez-Seoane S, Osborne PE, Alonso JC (2002) Large-scale habitat selection by agricultural steppe birds in Spain: identifying species-habitat responses using generalized additive models. J Appl Ecol 39:755–771CrossRefGoogle Scholar
  45. Tabachnick B, Fidell L (1996) Using multivariate statistics. HarperCollins Publishers Inc., New YorkGoogle Scholar
  46. Winter M, Faaborg J (1999) Varying patterns of “area-sensitivity” in grassland-nesting birds. Conserv Biol 13:1324–1434CrossRefGoogle Scholar
  47. Wolff A, Dieulevent T, Martin JL, Bretagnolle V (2002) Landscape context and little bustard abundance in a fragmented steppe: implications for reserve management in mosaic landscapes. Biol Conserv 107:211–220CrossRefGoogle Scholar
  48. Zar JH (1996) Biostatistical analysis. Prentice-Hall International, Inc., New JerseyGoogle Scholar

Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2013

Authors and Affiliations

  • João Paulo Silva
    • 1
    • 2
    Email author
  • Beatriz Estanque
    • 2
  • Francisco Moreira
    • 1
  • Jorge Manuel Palmeirim
    • 2
  1. 1.Centre for Applied Ecology “Prof. Baeta Neves”, Institute of AgronomyTechnical University of LisbonLisbonPortugal
  2. 2.Department of Animal Biology, Centre for Environmental Biology, Faculty of ScienceUniversity of LisbonLisbonPortugal

Personalised recommendations