Ground-nesting birds face many challenges to reproduce successfully, with nest predation being the main cause of reproductive failure. Visual predators such as corvids and egg-eating raptors, are among the most common causes of nest failure; thus, parental strategies that reduce the risk of visual nest predation should be favored by selection. To date, most research has focused on egg crypsis without considering adult crypsis, although in natural circumstances the eggs are covered by an incubating parent most of the time. Here we use a ground-nesting shorebird, the Kentish plover (Charadrius alexandrinus) as model species to experimentally test whether decoy parents influence nest predation. Using artificial nests with a male decoy, a female decoy or no decoy, we found that the presence of a decoy increased nest predation (N = 107 nests, p < 0.001). However, no difference was found in predation rates between nests with a male versus female decoy (p > 0.05). Additionally, we found that nests in densely vegetated habitats experienced higher survival compared to nests placed in sparsely vegetated habitats. Nest camera images, predator tracks and marks left on eggs identified the brown-necked raven (Corvus ruficollis) as the main visual nest predator. Our study suggests that the presence of incubating parents may enhance nest detectability to visual predators. However, parents may reduce the predation risk by placing a nest in sites where they are covered by vegetation. Our findings highlight the importance of nest site selection not only regarding egg crypsis but also considering incubating adult camouflage.

Centre for Ecological Research Danube Research Institute Budapest Hungary

Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom

Department of Biodiversity Research Global Change Research Institute Czech Academy of Sciences Prague Czech Republic

Department of Biology and Biochemistry Milner Centre for Evolution University of Bath Bath United Kingdom

Department of Evolutionary Zoology and Human Biology University of Debrecen Debrecen Hungary

Maio Biodiversity Foundation Maio Republic of Cape Verde

Senckenberg German Entomological Institute Müncheberg Germany

See more in PubMed

MacDonald MA, Bolton M. Predation on wader nests in Europe. Ibis. 2008. August;150(suppl.):54–73.

Roodbergen M, van der Werf B, Hötker H. Revealing the contributions of reproduction and survival to the Europe-wide decline in meadow birds: review and metanalysis. Journal of Ornithology. 2012. January 1;153(1):53–74.

Kubelka V, Šálek M, Tomkovich P, Végvári Z, Freckleton R, Székely T. Global pattern of nest predation is disrupted by climate change in shorebirds. Science. 2018. November 9;362(6415):680–3. 10.1126/science.aat8695 PubMed DOI

Martin TE. Processes organizing open-nesting bird assemblages: competition or nest predation? Evolutionary Ecology. 1988. January 1;2(1):37–50.

Martin TE. On the advantage of being different: nest predation and the coexistence of bird species. Proceedings of the National Academy of Sciences. 1988. April 1;85(7):2196–2199. PubMed PMC

Thompson FR. Factors affecting nest predation on forest songbirds in North America. Ibis. 2007. November 1;149(2):98–109.

Evans PR, Pienkowski MW. Population dynamics of shorebirds In: Burger J, Olla BL, editors. Shorebirds: Breeding behavior and populations. New York: Springer US; 1984. p. 83–123.

Colwell MA. Shorebird ecology, conservation, and management. Berkeley and Los Angeles, California: University of California Press; 2010. November 16.

Bennett PM, Owens IPF. Evolutionary Ecology of Birds: Life Histories, Mating Systems, and Extinction. Oxford: Oxford University Press; 2002.

Blackburn TM, Cassey P, Duncan RP, Evans KL, Gaston KJ. Avian extinction and mammalian introductions on oceanic islands. Science. 2004. September 24;305(5692):1955–1958. 10.1126/science.1101617 PubMed DOI

Martin TE. Avian life history evolution in relation to nest sites, nest predation, and food. Ecological Monographs. 1995. February;65(1):101–127.

Lima SL. Predators and the breeding bird: behavioral and reproductive flexibility under the risk of predation. Biological reviews of the Cambridge Philosophical Society. 2009. August;84:485–513. 10.1111/j.1469-185X.2009.00085.x PubMed DOI

Mainwaring MC, Reynolds SJ, Weidinger K. The influence of predation on the location and design of nests In: Deeming DC, Reynolds SJ, editors. Nests, Eggs and Incubation: New Ideas about Avian Reproduction. Oxford, United Kingdom: Oxford University Press; 2015. August 15 p. 50–64.

Kis J, Liker A, Székely T. Nest defense by lapwings: observations on natural behavior and an experiment. Ardea. 2000;88(2):155–163.

Caro T. Antipredator defenses in birds and mammals. Chicago: University of Chicago Press; 2005.

Kubelka V. Significance of predation for breeding ecology and conservation in shorebirds. PhD thesis, Charles University, Prague; 2018.

Stoddard MC, Kupán K, Eyster HN, Rojas-Abreu W, Cruz-López M, Serrano-Meneses MA, et al. Camouflage and clutch survival in plovers and terns. Scientific reports. 2016. September 12;6:32059 10.1038/srep32059 PubMed DOI PMC

del Hoyo J, Elliott A, Sargatal J. Handbook of the Birds of the World Vol 3: Hoatzin to Auks. Barcelona, Spain: Lynx Editions; 1996.

Šálek M, Zámečník V. Delayed nest predation: a possible tactic toward nests of open-nesting birds. Folia Zoologica. 2014. July;63(2):67–73.

Ekanayake KB, Weston MA, Nimmo DG, Maguire GS, Endler JA, Küpper C. The bright incubate at night: sexual dichromatism and adaptive incubation division in an open-nesting shorebird. Proceedings of the Royal Society B: Biological Sciences. 2015. May 7;282(1806):20143026 10.1098/rspb.2014.3026 PubMed DOI PMC

Cody ML, editor. Habitat selection in birds. Academic Press; 1985. June 28.

Martin TE. Nest predation among vegetation layers and habitat types: revising the dogmas. The American Naturalist. 1993. June 1;141(6):897–913. 10.1086/285515 PubMed DOI

Evans KL. The potential for interactions between predation and habitat change to cause population declines of farmland birds. Ibis. 2004. January;146(1):1–13.

Cunningham JA, Kesler DC, Lanctot RB. 2016. Habitat and social factors influence nest-site selection in Arctic-breeding shorebirds. The Auk: Ornithological Advances. 2016 May 4;133(3):364–377.

Olsen H, Schmidt NM. Response of hooded crow Corvus corone cornix and magpie Pica to exposure to artificial nests. Bird Study. 2004. March 1;51(1):87–90.

Vigallon SM, Marzluff JM, Burger AE. Is nest predation by Steller's Jays (Cyanocitta stelleri) incidental or the result of a specialized search strategy? The Auk. 2005. January 1;122(1):36–49.

Croze H. Searching image in Carrion Crows–hunting strategy in a predator and some anti-predator devices in camouflaged prey. Zeitschrift für Tierpsychologie, Beiheft. 1970;5:5–85.

Côté IM, Sutherland WJ. The Effectiveness of Removing Predators to Protect Bird Populations: Efectividad de la Remoción de Depredadores para Proteger Poblaciones de Aves. Conservation Biology. 1997. April 20;11(2):395–405.

Opermanis O. Appearance and vulnerability of artificial duck nests to avian predators. Journal of Avian Biology. 2004. September;35(5):410–415.

Trnka A, Prokop P, Batáry P. Dummy birds in artificial nest studies: an experiment with Red-backed Shrike Lanius collurio. Bird Study. 2008. November 1;55(3):329–331.

Swanson L, Sanyaolu RA, Gnoske T, Whelan CJ, Lonsdorf EV, Cordeiro NJ. Differential response of nest predators to the presence of a decoy parent in artificial nests. Bird study. 2012. February 1;59(1):96–101.

Eberhart-Phillips LJ. Breeding systems: diversity and evolutionary origins In: Colwell MA, Haig SM, editors. The population ecology and conservation of Charadrius plovers. 1st ed Boca Raton, Florida: CRC Press; 2019. p. 60–84.

Székely T. 2019. Why study plovers? The significance of non-model organisms in avian ecology, behaviour and evolution. Journal of Ornithology. 2019. July:1–11.

Oliveira A. Cape Verde designates salt flats for Ramsar List [Internet]. 2013. August 13 [cited 2019 May 9]. Available from: https://www.ramsar.org/news/cape-verde-designates-salt-flats-for-ramsar-list

Pereira Neves JM. Estratégia e Plano Nacional de Negócios das Áreas Protegidas. Boletim Oficial da Rebública de Cabo Verde. 2016;1(17):152–182.

Carmona-Isunza MC, Küpper C, Serrano-Meneses MA, Székely T. Courtship behavior differs between monogamous and polygamous plovers. Behavioral ecology and sociobiology. 2015. December 1;69(12):2035–2042.

Székely T, Kosztolányi A, Küpper C. Practical guide for investigating breeding ecology of Kentish plover Charadrius alexandrinus Unpublished Report, University of Bath, Bath; 2008. Available from: https://www.researchgate.net/publication/228494424_Practical_guide_for_investigating_breeding_ecology_of_Kentish_plover_Charadrius_alexandrinus

González JA, Triay-Portella R, Martins A, Lopes E. Checklist of brachyuran crabs (Crustacea: Decapoda) from the Cape Verde Islands, with a biogeographic comparison with the Canary Islands (Eastern Atlantic). Cahiers de Biologie Marine. 2017;58:137–51.

QGIS Development Team. QGIS Geographic Information System. Open Source Geospatial Foundation Project; 2019. Available from: http://qgis.osgeo.org

OpenMapTiles. OpenStreetMap contributors. Available from: https://openmaptiles.com/

Wickham H. ggplot2: Elegant Graphics for Data Analysis. New York, New York: Springer-Verlag; 2016.

Therneau T, Grambsch P. Modeling Survival Data: Extending the Cox Model. New York, New York: Springer Science & Business Media; 2013. November 11.

Therneau T. A Package for Survival Analysis in S. version 2.38; 2015. Available from: URL https://CRAN.R-project.org/package=survival.

Kassambara A. survminer R package: Survival Data Analysis and Visualization; 2016.

Hastie TJ, Pregibon D. Generalized linear models In: Chambers JM, Hastie TJ, editors. Statistical Models in S. Pacific Grove. California: Wadsworth & Brooks/Cole Advanced Books & Software; 1992.

R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria; 2014. Available from: URL http://www.R-project.org/.

Gómez-Serrano MÁ, López-López P. Nest site selection by Kentish plover suggests a trade-off between nest-crypsis and predator detection strategies. PloS one. 2014. September 10;9(9):107–121. PubMed PMC

Troscianko J, Wilson-Aggarwal J, Stevens M, Spottiswoode CN. Camouflage predicts survival in ground-nesting birds. Scientific Reports. 2016. January 29;6:19966 10.1038/srep19966 PubMed DOI PMC

Wilson-Aggarwal JK, Troscianko JT, Stevens M, Spottiswoode CN, 2016. Escape distance in ground-nesting birds differs with individual level of camouflage. The American Naturalist. 2016 August 1;188(2):231–239. 10.1086/687254 PubMed DOI

Gōtmark F. Black-and-white plumage in male pied flycatchers (Ficedula hypoleuca) reduces the risk of predation from sparrow hawks (Accipiter nisus) during the breeding season. Behavioral Ecology. 1995. March 1;6(1):22–26.

Carthey AJ, Blumstein DT. Predicting predator recognition in a changing world. Trends in ecology & evolution. 2018. February 1;33(2):106–15. PubMed

Salek M, Cepáková E. Do northern lapwings Vanellus vanellus and little ringed plovers Charadrius dubius rely on egg crypsis during incubation? Folia Zoologica. 2006. January 19;55(1):43–51.

Coates PS, Delehanty DJ. Nest predation of greater sage-grouse in relation to microhabitat factors and predators. Journal of Wildlife Management. 2010. February;74(2):240–248.

Rees JD, Webb JK, Crowther MS, Letnic M. Ravens are a key threat to beach-nesting birds. Australian Field Ornithology. 2015. June;32(2):100.

Marzluff JM, Neatherlin E. Corvid response to human settlements and campgrounds: causes, consequences, and challenges for conservation. Biological conservation. 2006. June 1;130(2):301–314.

Wellins CA, Rittschof D, Wachowiak M. Location of volatile odor sources by ghost crab Ocypode quadrata (Fabricius). Journal of Chemical Ecology. 1989. April 1;15(4):1161–1169. 10.1007/BF01014819 PubMed DOI

Lucrezia S, Schlacher TA. The ecology of ghost crabs. Oceanography and Marine Biology: An Annual Review. 2014;52:201–256.

Whittaker RJ, Fernández-Palacios JM, Matthews TJ, Borregaard MK, Triantis KA. Island biogeography: Taking the long view of nature’s laboratories. Science. 2017. September 1;357(6354):1–7. PubMed

Melvin SM, MacIvor LH, Griffin CR. Predator exclosures: a technique to reduce predation at piping plover nests. Wildlife Society Bulletin. 1992;20(2):143–148.

Murphy RK, Michaud IM, Prescott DR, Ivan JS, Anderson BJ, French-Pombier ML. Predation on adult piping plovers at predator exclosure cages. Waterbirds. 2003. June;26(2):150–156.

Isaksson D, Wallander J, Larsson M. Managing predation on ground-nesting birds: The effectiveness of nest exclosures. Biological Conservation. 2007. April 1;136(1):136–142.

Pauliny A, Larsson M, Blomqvist D. 2008. Nest predation management: effects on reproductive success in endangered shorebirds. Journal of Wildlife Management. 2008. September;72(7):1579–158.

Smith RK, Pullin AS, Stewart GB, Sutherland WJ. 2010. Effectiveness of predator removal for enhancing bird populations. Conservation Biology. 2010. June;24(3):820–829. 10.1111/j.1523-1739.2009.01421.x PubMed DOI

Moore RP, Robinson WD. 2004. Artificial bird nests, external validity, and bias in ecological field studies. Ecology. 2004. June;85(6):1562–1567.