Article

Improvement of individual camouflage through background choice in ground-nesting birds

  • Nature Ecology & Evolution 113251333 (2017)
  • doi:10.1038/s41559-017-0256-x
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Abstract

Animal camouflage is a longstanding example of adaptation. Much research has tested how camouflage prevents detection and recognition, largely focusing on changes to an animal’s own appearance over evolution. However, animals could also substantially alter their camouflage by behaviourally choosing appropriate substrates. Recent studies suggest that individuals from several animal taxa could select backgrounds or positions to improve concealment. Here, we test whether individual wild animals choose backgrounds in complex environments, and whether this improves camouflage against predator vision. We studied nest site selection by nine species of ground-nesting birds (nightjars, plovers and coursers) in Zambia, and used image analysis and vision modelling to quantify egg and plumage camouflage to predator vision. Individual birds chose backgrounds that enhanced their camouflage, being better matched to their chosen backgrounds than to other potential backgrounds with respect to multiple aspects of camouflage. This occurred at all three spatial scales tested (a few centimetres and 5 m from the nest, and compared with other sites chosen by conspecifics) and was the case for the eggs of all bird groups studied, and for adult nightjar plumage. Thus, individual wild animals improve their camouflage through active background choice, with choices highly refined across multiple spatial scales.

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Acknowledgements

J.T., J.K.W.-A. and M.S. were funded by a Biotechnology and Biological Sciences Research Council (BBSRC) grant BB/J018309/1 to M.S., and a BBSRC David Phillips Research Fellowship (BB/G022887/1) to M.S. C.N.S was funded by a Royal Society Dorothy Hodgkin Fellowship, a BBSRC David Phillips Fellowship (BB/J014109/1) and the DST-NRF Centre of Excellence at the FitzPatrick Institute. In Zambia, we thank the Bruce-Miller, Duckett and Nicolle families, C. Moya and numerous other nest-finding assistants and land owners, L. Chama, and the Zambia Wildlife Authority. We also thank R. Douglas for supplying lens transmission data for the ferret.

Author information

Affiliations

  1. Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK

    • Martin Stevens
    • , Jolyon Troscianko
    •  & Jared K. Wilson-Aggarwal
  2. Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK

    • Claire N. Spottiswoode
  3. DST-NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, 7701, South Africa

    • Claire N. Spottiswoode

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Contributions

All authors designed and conceived the study. Fieldwork was conducted by J.T., J.K.W.-A. and C.N.S. at a study site set up by C.N.S. Image analysis and vision modelling was carried out by J.T., J.K.W.-A. and M.S., and the statistical analysis primarily by J.T. M.S. wrote the initial manuscript, which was reviewed and approved by all authors prior to submission.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Martin Stevens.

Electronic supplementary material

  1. Supplementary Information

    Supplementary Discussion

  2. Supplementary Data

    Egg microhabitat data and adult nightjar microhabitat data