ORIGINAL PAPER High begging intensity of great spotted cuckoo nestlings favours larger-size crow nest mates Diana Bolopo & Daniela Canestrari & María Roldán & Vittorio Baglione & Manuel Soler Received: 10 December 2014 /Revised: 23 February 2015 /Accepted: 24 February 2015 # Springer-Verlag Berlin Heidelberg 2015 Abstract In nests of birds parasitized by a larger non-evicting brood parasite, host chicks typically are at disadvantage in competing for food and often starve. However, when host chicks are larger, they may benefit from the presence of the parasite, which contributes to the net brood begging signal but cannot monopolize the food brought to the nest. Here, we show that, despite a higher begging intensity, great spotted cuckoos (Clamator glandarius) did not outcompete larger size carrion crow (Corvus corone corone) nestlings. Furthermore, cuckoos’ exaggerated begging allowed crow nest mates to decrease their begging intensity without negative conse- quences on food intake. Assuming an energetic cost to chicks of begging intensely, our results suggest that crow chicks sharing the nest with a cuckoo may obtain an advantage that should be weighed against the loss of indirect fitness due to parasitism. Keywords Brood parasitism . Corvus corone . Clamator glandarius . Cuckoo . Begging . Nestling provisioning Introduction Avian interspecific brood parasitism provides an ideal model to study co-evolution (Rothstein 1990; Soler and Soler 2000; Kilner and Langmore 2011; Roldán and Soler 2011; Spottiswoode et al. 2012; Feeney et al. 2014; Soler 2014). From the parasite’ s point of view, the lack of siblings in the nest favours the evolution of strategies that maximize their own survival at the expense of nest mates (Godfray 1995; Lichtenstein 2001). Some brood parasites indeed evict host eggs/chicks from the nest (Rothstein 1990; Honza et al. 2006), kill host hatchlings (Spottiswoode and Koorevaar 2012), or beg exaggeratedly to monopolize the food provi- sioned by the foster parents (Dearborn 1998). These strategies pose costs to the hosts that range from moderate (one or more host chicks can fledge) to severe (loss of the entire host clutch). This gradient of parasite virulence (Kilner 2005) is likely to determine the variation in the evolution of host de- fences (Servedio and Hauber 2006; Spottiswoode et al. 2012), such as recognition and ejection of foreign eggs and/or chicks (Davies and Brooke 1989; Langmore et al. 2003; Davies 2011), desertion of parasitized nests (Krüger 2011; Moskat et al. 2011), and mobbing of parasitic adults (Soler et al. 1999a; Roskaft et al. 2002; Welbergen and Davies 2009). Communicated by M. Leonard Electronic supplementary material The online version of this article (doi:10.1007/s00265-015-1895-z) contains supplementary material, which is available to authorized users. D. Bolopo : V. Baglione Department of Agro-forestry, University of Valladolid, Valladolid, Spain D. Canestrari Department of Biology of Organisms and Systems (BOS), University of Oviedo, Oviedo, Spain D. Canestrari (*) Research Unit of Biodiversity (UMIB, CSIC, UO), Oviedo, Spain e-mail: canestraridaniela@uniovi.es M. Roldán : M. Soler Department of Zoology, University of Granada, Granada, Spain V. Baglione Sustainable Forest Management Research Institute, Palencia, Spain M. Soler Grupo Coevolución, Unidad Asociada al CSIC, Universidad de Granada, Granada, Spain Behav Ecol Sociobiol DOI 10.1007/s00265-015-1895-z