Scaling up ideals to freedom: Are densities of Red Knots across western Europe consistent with ideal free distribution?

Gwenael Quaintenne*, Jan A. van Gils, Pierrick Bocher, Anne Dekinga, Theunis Piersma

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

36 Citations (Scopus)

Abstract

Local studies have shown that the distribution of red knots Calidris canutus across intertidal mudflats is consistent with the predictions of an ideal distribution, but not a free distribution. Here, we scale up the study of feeding distributions to their entire wintering area in western Europe. Densities of red knots were compared among seven wintering sites in The Netherlands, UK and France, where the available mollusc food stocks were also measured and from where diets were known. We tested between three different distribution models that respectively assumed (i) a uniform distribution of red knots over all areas, (ii) a uniform distribution across all suitable habitat (based on threshold densities of harvestable mollusc prey), and (iii) an ideal and free distribution (IFD) across all suitable habitats. Red knots were not homogeneously distributed across the different European wintering areas, also not when considering suitable habitats only. Their distribution was best explained by the IFD model, suggesting that the birds are exposed to interference and have good knowledge about their resource landscape at the spatial scale of NW Europe, and that the costs of movement between estuaries, at least when averaged over a whole winter, are negligible.

Original languageEnglish
Pages (from-to)2728-2736
Number of pages9
JournalProceedings of the Royal Society of London. Series B, Biological Sciences
Volume278
Issue number1719
DOIs
Publication statusPublished - 22-Sep-2011

Keywords

  • dispersal
  • energetics
  • group living
  • intake rate
  • interference
  • spatial scale
  • AFFECTS FORAGING DECISIONS
  • LONG-DISTANCE MIGRATION
  • COST-BENEFIT-ANALYSIS
  • CALIDRIS-CANUTUS
  • HABITAT SELECTION
  • WADDEN SEA
  • INTERFERENCE COMPETITION
  • CONSPECIFIC ATTRACTION
  • HAEMATOPUS-OSTRALEGUS
  • SPATIAL-DISTRIBUTION

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