Great spotted cuckoo fledglings are disadvantaged by magpie host parents when reared together with magpie nestlings
The post-fledging period is a critical phase for juvenile survival, and parental care provided during this period is a key component of avian reproductive performance. Very little is known about the relationships between foster parents and fledglings of brood parasites. Here, we present the results of a 5-year study about the relationships between fledglings of the non-evictor brood parasitic great spotted cuckoo (Clamator glandarius) and its magpie (Pica pica) foster parents. Sometimes, great spotted cuckoo and magpie nestlings from the same nest can fledge successfully, but most often parasitic nestlings outcompete host nestlings and only cuckoos leave the nest. We have studied several aspects of cuckoo post-fledging performance (i.e. feeding behaviour, parental defence and fledgling survival) in experimental nests in which only cuckoos or both magpie and cuckoo nestlings survived until leaving the nest. The results indicate that great spotted cuckoo fledglings reared in mixed broods together with magpie nestlings were disadvantaged by magpie adults with respect to feeding patterns. Fledgling cuckoos reared in mixed broods were fed less frequently than those reared in only cuckoo broods, and magpie adults approached less frequently to feed cuckoos from mixed broods than cuckoos from only cuckoo broods. These results imply that the presence of host's own nestlings for comparison may be a crucial clue favouring the evolution of fledgling discrimination; and furthermore, that the risk of discrimination at the fledgling stage probably is an important selection pressure driving the evolution of the arms race between brood parasites and their hosts.
KeywordsBrood parasitism Clamator glandarius Fledgling discrimination Fledgling period Non-evictor brood parasitic chicks Pica pica
We thank Francisco Espinosa, Francisco Ferri and Juan S. Sanchez for their help with field work. This work was supported by the Spanish Ministerio de Economía y Competitividad/FEDER (research project CGL2011-25634/BOS). We also thank Tomas Grim, the Associate Editor and two anonymous reviewers for constructive comments on a previous version of the manuscript, which considerably improved and clarified the text.
Research has been conducted according to relevant Spanish national (Real Decreto 1201/2005, de 10 de Octubre) and regional (permissions provided yearly by la Consejería de Medio Ambiente de la Junta de Andalucía) guidelines.
- Davies NB (2000) Cuckoos, cowbirds and other cheats. T & AD Poyser, LondonGoogle Scholar
- Fraga RM (1998) Interactions of the parasitic screaming and shiny cowbirds (Molothrus rufoaxillaris and M. bonariensis) with a shared host, the bay-winged cowbird (M. badius). In: Rothstein SI, Robinson SK (eds) Parasitic birds and their hosts: studies in coevolution. Oxford University Press, New York, pp 173–193Google Scholar
- Grim T (2006a) The evolution of nestling discrimination by hosts of parasitic birds: why is rejection so rare? Evol Ecol Res 8:785–802Google Scholar
- Grim T (2006b) Low virulence of brood parasitic chicks: adaptation or constraint? Ornithol Sci 5:237–242Google Scholar
- Kershner EL, Walk JW, Warner RE (2004) Postfledging movements and survival of juvenile eastern meadowlarks (Sturnella magna) in Illinois. Auk 121:1146–1154Google Scholar
- Rappole JH, Tipton AR (1991) New harness design for attachment of radio transmitters to small passerines. J Field Ornithol 62:335–337Google Scholar
- Skutch AF (1976) Parent birds and their young. Texas University Press, AustinGoogle Scholar
- Skutch AF (1996) Orioles, blackbirds, and their kin: a natural history. University of Arizona Press, Tucson, AZGoogle Scholar
- Soler M (2002) Breeding strategy and begging intensity: influences on food delivery by parents and host selection by parasitic cuckoos. In: Wright J, Leonard ML (eds) The evolution of begging. Competition, cooperation and communication. Kluwer Academic, Dordrecht, pp 413–427Google Scholar
- Soler M, Martínez JG, Soler JJ (1996) Effects of brood parasitism by the great spotted cuckoo on the breeding success of the magpie host: an experimental study. Ardeola 43:87–96Google Scholar
- Soler M, Soler JJ, Martínez JG (1998) Duration of sympatry and coevolution between the great spotted cuckoo (Clamator glandarius) and its primary host, the magpie (Pica pica). In: Rothstein SI, Robinson SK (eds) Parasitic birds and their hosts: studies in coevolution. Oxford University Press, New York, pp 113–128Google Scholar
- Soler M, Soler JJ, Martínez JG, Moreno J (1999b) Begging behaviour and its energetic cost in great spotted cuckoo and magpie host chicks. Can J Zool 77:1794–1800Google Scholar
- Wyllie J (1981) The cuckoo. B Y Batsford Ltd, LondonGoogle Scholar