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Is the large-scale decline of the starling related to local changes in demography?

Author:
  • Henrik Smith
  • Annika Ryegard
  • Sören Svensson
Publishing year: 2012
Language: English
Pages: 741-748
Publication/Series: Ecography
Volume: 35
Issue: 8
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

The decline of one farmland bird, the migratory European starling, has been attributed to both agricultural intensification and farmland abandonment and to factors operating both during the winter and during the breeding season. We analysed population data from thirty-three Swedish nestbox colonies over more than two decades to determine if the national decline was caused by a common factor affecting all colonies or by local changes in the breeding grounds affecting starling colonies. We found that numbers of breeding starling had declined significantly, but at different rates in different colonies. The local population sizes were affected by previous years productivity at both national and local scales, suggesting that changes in habitat quality at both scales could affect local population trends. There were no long-term trends in reproductive output, but fledgling production was lowest at intermediate years. The local population changes were positively related to local changes in reproductive output, but only when including complete nest-failures. A relationship between population declines and low mean local productivity was the result of the association between population sizes and reproductive success over time, since decline rates of starlings were not related to the average success during the first part of the study, but to the average success during the later part of the study. The relationship between population change and changes in reproductive output was evident, but fledgling production showed negative density-dependence. In conclusion this study suggests that the decline of the starling population in Sweden has been affected by processes at small spatial scales during the breeding season affecting reproductive success, but does not exclude an additional role for processes at large spatial scales or outside the breeding season.

Keywords

  • Earth and Related Environmental Sciences
  • Ecology

Other

Published
  • BECC
  • ISSN: 1600-0587
Henrik Smith
E-mail: henrik.smith [at] biol.lu.se

Professor

Biodiversity

+46 46 222 93 79

+46 70 978 20 56

E-C313

50

Director

Centre for Environmental and Climate Research (CEC)

+46 46 222 93 79

+46 70 978 20 56

C313

Sölvegatan 37, Lund

50

Centre for Animal Movement Research
Evolutionary Ecology, Department of Biology
Ecology building S-223 62 Lund Sweden