Abstract
This paper describes at a regional scale the distribution pattern, density, productivity and sex ratio of great bustards in northwestern Spain and explores the role played by habitat type, terrain characteristics and human disturbance on variation in its demographic parameters. Data from 136 plots covering an area of 7314 km2 were obtained in two censuses carried out in the spring and summer of 1998. The density of the great bustards was 1.39 individuals/km2 in the pre-breeding period, decreasing by 22% in the post-breeding period. Density was significantly higher in central plots than in peripheral plots. Mean productivity was 0.24 chicks per female and showed a high variability among plots, being significantly lower in the densest plots. The overall sex ratio was 1.35 females per male during the pre-breeding period. Productivity related positively to areas holding small fields and a high interspersion of land uses. Density and productivity were negatively affected by river density and altitude, and seasonal density variation was positively correlated with human population density.
Similar content being viewed by others
References
Alonso JC, Morales MB, Alonso JA (2000) Partial migration, lek fidelity and nesting area fidelity in female great bustards Otis tarda. Condor 102:127–136
Alonso JC, Palacín C, Martín CA (2003a) Status and recent trends of the great bustard (Otis tarda) population in the Iberian Peninsula. Biol Conserv 110:185–195
Alonso JC, Martín CA, Palacín C, Magaña M, Martín B (2003b) Distribution, size and recent trends of the Great Bustard Otis tarda population in Madrid region, Spain. Ardeola 50:21–29
Alonso JC, Martín CA, Alonso JA, Palacín C, Magaña M, Lane SJ (2004) Distribution dynamics of a great bustard metapopulation throughout a decade: influence of conspecific attraction and recruitment. Biodivers Conserv 13:1659–1674
BirdLife International (2004) Threatened birds of the world 2004 CD-ROM. BirdLife International, Cambrige
Blackburn TM, Gaston KJ, Quinn RM, Gregory RD (1999) Do local abundances of British birds change with proximity to range edge? J Biogeogr 26:493–505
Brown JH, Mehlman DW, Stevens GC (1995) Spatial variation in abundance. Ecology 76:2028–2043
Burel F, Baudry J (1995) Farming landscapes and insects. In: Glen DM, Greaves MP, Anderson HM (eds) Ecology and integrated farming systems. Wiley, Chichester, pp 203–220
Collar NJ (1985) The world status of the Great Bustard. Bustard Stud 2:1–20
Chan S, Goroshko O (1998) Action plan for the great bustard Otis tarda in Asia. BirdLife International, Tokyo
Collar NJ, Crosby MJ, Stattersfield AJ (1994) Birds to watch 2: The world list of threatened birds. BirdLife conservation series No 4. BirdLife International, Cambridge
Del Hoyo J, Elliot A, Sargatal J (1996) Handbook of the birds of the world, vol 3. Lynx, Barcelona
Dhondt AA, Kempeaners B, Adriaensen F (1992) Density-dependent clutch size caused by habitat heterogeneity. J Anim Ecol 61:643–648
Gaston KJ, Blackburn TM, Gregory RD (1999) Does variation in census area confound density comparisons? J Appl Ecol 36:191–204
González LM, Bustamante J, Hiraldo F (1992) Nesting habitat selection by the Spanish imperial eagle Aquila adalberti. Biol Conserv 59:45–50
Hall RL (1995) Plant diversity in arable ecosystems. In: Glen DM, Greaves MP, Anderson HM (eds) Ecology and integrated farming systems. Wiley, Chichester, pp 9–15
Lane SJ, Alonso JC, Martín C (2001) Habitat preferences of great bustard Otis tarda flocks in the arable steppes of central Spain: are potentially suitable areas unoccupied? J Appl Ecol 38:193–203
Martín E (1997) Dispersión juvenil y cuidado maternal en la avutarda (Otis tarda). PhD thesis. Universidad Autónoma, Madrid
Martín CA (2001) Dispersión y estructura genética de la población de avutardas de la Comunidad de Madrid. PhD thesis. Universidad Autónoma, Madrid
Martínez C (1991) Patterns of distribution and habitat selection of a Great bustard (Otis tarda) population in Northwest Spain. Ardeola 38:137–147
Martínez C (1999) La avutarda (Otis tarda) en Castilla y León. Situación actual y estado de conservación. Medio Ambiente en Castilla y León 12:11–19
Martínez C (2000) Daily activity patterns of great bustards Otis tarda. Ardeola 47:57–68
Morales MB (1999) Ecología reproductiva y movimientos estacionales en la avutarda (Otis tarda). PhD thesis. Universidad Complutense, Madrid
Morales MB, Alonso JC, Alonso JA, Martín E (2000) Migration patterns in male great bustards. Auk 117:493–498
Morales MB, Alonso JC, Alonso JA (2002) Annual productivity and individual female reproductive success in a great bustard Otis tarda population. Ibis 144:293–300
Osborne PE, Alonso JC, Bryant RG (2001) Modelling landscape-habitat using GIS and remote sensing: a case study with great bustards. J Appl Ecol 38:458–471
Palacín C, Alonso JC, Martín CA, Magaña M, Martín B (2004) Avutarda Común (Otis tarda). In: Madroño A, González C, Atienza JC (eds) Libro Rojo de las Aves de España. SEO/BirdLife and Dirección General de Conservación de la Naturaleza, Ministerio de Medio Ambiente, Madrid, pp 209–213
Pulliam HR, Danielson BJ (1991) Sources, sinks and habitat selection: a landscape perspective on population dynamics. Am Nat 137:50–66
Sinclair ARE (1989) Population regulation in animals. In: Cherrett JF (ed) Ecological concepts. Blackwell, Oxford, pp 197–241
Siriwardena GM, Baillie SR, Crick HQP, Wilson JD (2001) Changes in agricultural land-use and breeding performance of some granivorous farmland passerines in Britain. Agr Ecos Environ 84:191–206
Smith AT, Peacock MM (1990) Conspecific attraction and the determination of metapopulation colonization rates. Conserv Biol 4:320–323
SPSS (2003) SPSS for Windows, version 11.5. SPSS, Chicago
Stamps JA (1988) Conspecific attraction and aggregation in territorial species. Am Nat 131:329–347
Van Horne B (1983) Density as a misleading indicator of habitat quality. J Wildl Manage 47:893–901
Wiens JA (1989) Spatial scaling in ecology. Funct Ecol 3:385–397
Wiens JA, Rotenberry JT, Van Horne B (1987) Habitat occupancy patterns of North American shrubsteppe birds: the effects of spatial scale. Oikos 48:132–147
Acknowledgments
This study was funded by the Consejería de Medio Ambiente y Ordenación del Territorio of the Junta de Castilla y León and carried out by ETI. The components of the census teams were: A. Almodóvar, B. Campos, G. Castillo, A. Contreras, L. Fernández, J. M. García, E. Gómez, I. Martín, L, Martín, E. Martínez, N. Moreno, M. Muñoz, C. Palacín, J. Ramos, P. Refoyo, J. I. Regueras, L. Robles, L. Sánchez-Mármol, J. M. Santiago, V. Sanz and F. J. Urcaregui. T. Santos, M. Morales, L. M. Bautista, C. Palacín, J. Wilson, P. Vickery, Graham Martin and one anonimous referee provided valuable criticisms on a early version of the manuscript. C. Mediavilla helped with the figures and H. Burlmer reviewed the English translation.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by F. Bairlein.
Rights and permissions
About this article
Cite this article
Martínez, C. Distribution, density and productivity of great bustards Otis tarda in northwestern Spain: a regional approach. J Ornithol 149, 507–514 (2008). https://doi.org/10.1007/s10336-008-0296-8
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10336-008-0296-8