BUSCADOR RECOLECTA

Host defences against cuckoo parasitism and cuckoo trickeries to overcome them are a classic example of antagonistic coevolution. Recently it has been reported that this relationship may turn to be mutualistic in the case of the carrion crow (Corvus corone) and its brood parasite, the great spotted cuckoo (Clamator glandarius), given that experimentally and naturally parasitized nests were depredated at a lower rate than non-parasitized nests. This result was interpreted as a consequence of the antipredatory properties of a fetid cloacal secretion produced by cuckoo nestlings, which presumably deters predators from parasitized host nests. This potential defensive mechanism would therefore explain the detected higher fledgling success of parasitized nests during breeding seasons with high predation risk. Here, in a different study population, we explored the expected benefits in terms of reduced nest predation in naturally and experimentally parasitized nests of two different host species, carrion crows and magpies (Pica pica). During the incubation phase non-parasitized nests were depredated more frequently than parasitized nests. However, during the nestling phase, parasitized nests were not depredated at a lower rate than non-parasitized nests, neither in magpie nor in carrion crow nests, and experimental translocation of great spotted cuckoo hatchlings did not reveal causal effects between parasitism state and predation rate of host nests. Therefore, our results do not fit expectations and, thus, do not support the fascinating possibility that great spotted cuckoo nestlings could have an antipredatory effect for host nestlings, at least in our study area. We also discuss different possibilities that may conciliate these with previous results, but also several alternative explanations, including the lack of generalizability of the previously documented mutualistic association., Peer reviewed

Data file includes information about identity of each sampled individual, the species id, nest type, age, biometric measurements, the mean of the antagonistic halos shown against each 9 indicator bacteria, the antagonistic activity (average values of the width of antagonistic halos (mm) when tested against each of the nine indicator bacteria), the antagonistic range (Shannon index of the antagonistic activity) and the total density of bacteria on the gland., Ester Martínez Renau was financed by a predoctoral contract PRE2018-085378) while the whole research group received funds from the projects CGL2017-83103-P, PID2020-117429GB-C21 and PID2020-117429GB-C22, funded by the Ministerio de Ciencia e Innovación/Agencia Estatal de Investigación/10.13039/501100011033 and by “Fondo Europeo de Desarrollo Regional, a way of making Europe, Peer reviewed

Reflectance of mouth, rictal flange and body skin at the beginning of the treatment with cyproheptadine Spectral reflectance (300nm to 700nm) of three begging-related traits of magpie nestlings: mouth (gape or palate), rictal flange and body skin at the beginning of the treatment with cyproheptadine (nestlings 2–4 days old). Values are means obtained from three replicates and corrected by a triangular smoothing (i.e. a floating mean with weights within a distance of 10nm). Before_experimemt_reflectance_300_700nm.txt Reflectance of mouth, rictal flange and body skin at the end of the treatment with cyproheptadine Spectral reflectance (300nm to 700nm) of three begging-related traits of magpie nestlings: mouth (gape or palate), rictal flange and body skin at the end of the treatment with cyproheptadine (nestlings 10–12 days old). Values are means obtained from three replicates and corrected by a triangular smoothing (i.e. a floating mean with weights within a distance of 10nm). After_experimemt_reflectance_300_700nm.txt Irradiance inside 10 active magpie nests Irradiance measurements were performed in 10 active magpie nests between March and April of 2009, and between 09:00am and 11:00am in a magpie population in Guadix (Spain). It was done by placing the probe above the nest cup and pointing vertically toward the dome. Values are means per each nest from three replicates. Irradiance_inside_nests_300_700nm_moles_means.txt Nestling weights and colour measurements for the three begging-related traits before and after the treatment with cyproheptadine data_set_Martin-Galvez_and_Soler_2016.xlsx, The colouration of some traits in nestlings of altricial birds may influence parental food allocation as it may reflect physical condition or hunger. There is increasing evidence of the relationship between colouration of begging traits and nestling performance. However, evidence of the influence of hunger level on nestling colouration is scarce, mainly because of difficulty of distinguishing between the effects of physical condition and hunger levels. Here, we used the appetite stimulant cyproheptadine hydrochloride to increase the sensation of hunger of magpie (Pica pica) nestlings for eight days and assessed the effect on the colouration of rictal flanges, mouth and body skin. We found that nestlings administered with cyproheptadine had flanges more conspicuous (chromatic visual contrast), more UV coloured and less yellow coloured than their control nestmates. Conversely, mouths of experimental nestlings were more yellow coloured and less UV coloured than controls. Our pharmacological experiment affected the strength of the relationship between body mass and some colour components of body skin (chromatic and achromatic visual contrasts, UV–chroma and Yellow–chroma) and of rictal flanges (chromatic visual contrasts, UV–chroma and yellow–chroma), but not for mouth colouration. These results taken together suggest that the effect of the cyproheptadine on nestling colourations is probably mediated by an increase in hunger levels of nestlings for rictal flanges and body skin colourations, and by an increase in physical condition in the case of mouth coloration., Peer reviewed

Metadata Dataset used in this manuscript: results of the experiment and field measures. Abbreviations: 0, 120, 480 h (weight): concentration of oligopeptides at 0, 120 and 480 hours of the experiment. Data are corrected by the weight of each feather piece. metadata_RuizRodriguezetal.pdf, 1.Mechanisms guaranteeing reliability of messages are essential in understanding the underlying information and evolution of signals. Microorganisms may degrade signalling traits and therefore, influence the transmitted information and evolution of these characters. The role of microorganisms in animal signalling has, however, rarely been investigated. 2.Here, we explore a possible role for feather-degrading bacteria driving the design of ornamental throat feathers in male spotless starlings (Sturnus unicolor). We estimated length, bacterial load, degradation status, and susceptibility to degradation by keratinolytic bacteria in those feathers, compared to non-ornamental adjacent feathers in males, as well as to throat feathers in females. In addition, the volume of the uropygial gland and its secretion was measured, and the secretion extracted. We also experimentally evaluated the capacity of each secretion to inhibit growth of a keratinolytic bacterium. 3.The apical part of male ornamental throat feathers harboured more bacteria and degraded more quickly than the basal part; these patterns were not detected in female throat feathers or in non-ornamental male feathers. Moreover, degradation status of male and female throat feathers did not differ, but was positively associated with feather bacterial density. Finally, the size of the uropygial gland in both males and females predicted volume and the inhibitory capacity of secretion against feather-degrading bacteria. Only in males was uropygial gland size negatively associated with the level of feather degradation. 4.All results indicate differential susceptibility of different parts of throat feathers to keratinolytic bacterial attack, which supports the possibility that throat feathers in starlings reflect individual ability to combat feather-degrading bacteria honestly. This is further supported by the relationship detected between antimicrobial properties of uropygial secretion and the level of feather degradation. 5.Our results suggest that selection pressures exerted by feather-degrading bacteria on hosts may promote evolution of particular morphologies of secondary sexual traits with different susceptibility to bacterial degradation that reliably inform of their bacterial load. Those results will help to understand the evolution of ornamental signals., Peer reviewed

Telomere length of magpie and great spotted cuckoo nestlings Telomere length of magpie and great spotted cuckoo nestlings soon after hatching and before fledging. We also show telomere attrition values and laying-date of each studied nest. Values are means estimates per study nest. data.xlsx, Although little is known on the impact of environment on telomere length dynamics, it has been suggested to be affected by stress, lifestyle and/or life-history strategies of animals. We here compared telomere dynamics in erythrocytes of hatchlings and fledglings of the brood parasite great spotted cuckoos (Clamator glandarius) and of magpies (Pica pica), their main host in Europe. In magpie chicks, telomere length decreased from hatching to fledging while no significant change in telomere length of great spotted cuckoo chicks was found. Moreover, we found interspecific differences in the association between laying date and telomere shortening. Interspecific differences in telomere shortening were interpreted as a consequence of differences in lifestyle and life-history characteristics of magpies and great spotted cuckoos. In comparison with magpies, cuckoos experience reduced sibling competition and higher access to resources, and, consequently, lower stressful environmental conditions during the nestling phase. These characteristics also explain the associations between telomere attrition and environmental conditions (i.e. laying date) for magpies and the absence of association for great spotted cuckoos. These results therefore fit expectations on telomere dynamics derived from interspecific differences in lifestyle and life-history of brood parasites and their bird hosts., Peer reviewed

[Usage Notes] Table S1: The table includes data of juvenile whiteness (ventral and tail/wing whiteness), average clutch size, the species body mass, the number of broods and predation rate. trees: This file includes 100 trees downloaded from Birdtree.org for the 210 bird species used in the main analyses., The offspring of many animals are conspicuous during parental dependence, despite juveniles generally suffering from high predation risk. However, to date, it is unclear whether offspring structural ornaments play a role in intra-family communication. This is the case of conspicuous plumage in young birds, which is worn unchanged during a long period after fledging, when they still depend on their parents. If plumage color facilitates intra-family interactions, its role should be more important in large-brooded species, where the strength of intra-family conflict is potentially stronger. We therefore performed a comparative study in 210 passerine bird species to test whether an offspring structural trait, white plumage, evolves more frequently in lineages with larger clutches. We also explored the number of broods raised per year as another source of intra-family conflict. First, we found that juvenile whiteness was more frequent in open-nesting species. Moreover, in agreement with our prediction, the presence of juvenile white tail/wing patches was strongly and positively associated with clutch size. This relationship was not due to the strong resemblance between offspring and adult plumage, which was controlled for in the statistical analyses. Moreover, the association remained significant after taking into account predation risk, for which there was information for a subset of species. In contrast, juvenile whiteness was not associated with the number of broods raised per year. These results may suggest that the evolution of juvenile conspicuousness is favored in species with potentially stronger intra-brood sibling conflict., Peer reviewed

Dataset 1 includes weekly estimations of median, maximum, minimum and range values of temperature and humidity in nest boxes, for three locations, two experimental treatments and in relation to dormice presence in February., Dataset 2 includes daily differences (between 9:00 am and 3:00 am) in temperature and humidity of open nest boxes occupied or not by dormice., Dataset 3 describes Carnus emergence patterns from each sample of nest material, including number of emerged flies (Carnus abundance), date of first emergence and emergence duration., Dataset 4 includes intensity of parasitism suffered by hoopoe nestlings during the breeding season after the experiment, showing number of Carnus, hatching date, brood size and nestling age., The dataset contains data collected in Guadix, Granada (southeast Spain) in 2020, in the framework of a research to evaluate the effects of overwinter occupancy of nest cavities on the incidence of ectoparasitism suffered by hoopoes (Upupa epops) in the next breeding season., The research group benefited from grants CGL2017-83103-P, CGL2017-89063-P, PGC2018-097426-B-C22, and PID2020-117429GB-C21 funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe”. AJGN was funded by the Spanish Ministerio de Ciencia, Innovación y Universidades (Programa de Formación de Personal Investigador JAE Intro). GT was supported by the Ramón y Cajal Programme (RYC-2013-13040)., Peer reviewed

[How to contribute] For any problems downloading the data or for additional information, please send us an email and we will provide you with the necessary information. We would also appreciate your feedback regarding potential errors., [Ethics statement] All procedures were conducted according to relevant Spanish national (Decreto 105/2011, 19 de abril) and regional guidelines. Necessary permits for hoopoe manipulation were provided by Consejería de Medio Ambiente de la Junta de Andalucía, Spain (Ref: SGYB/FOA/AFR/CFS and SGMN/GyB/JMIF). All applicable guidelines for the care and use of animals were followed., We discuss the potential adaptive functions of laying optimistic clutch sizes that hatch asynchronously in hoopoes, a bird species with frequent sibling cannibalism. The production of extra eggs could serve as insurance against hatching failures, while the surplus hatchlings can be used as food and increase the probability of survival of their older siblings. Two experiments were conducted to explore the adaptative functions of producing extra offspring, one involving food supplementation during the egg-laying period, and the other manipulating brood size and hatching span. Results showed that females with extra food laid one more egg on average and that adding an extra egg that hatched the last increased sibling cannibalism and fledging success. These findings suggest that hoopoes are able to recover part of the cost of producing large clutches by consuming surplus chicks., The research group received funds from the projects PID2020-117429GB-C21 and PID2020-117429GB-C22, funded by the Ministerio de Ciencia e Innovación/Agencia Estatal de Investigación/10.13039/501100011033 and by “Fondo Europeo de Desarrollo Regional, a way of making Europe”. We also benefited from facilities, including an apartment, provided by the city authorities of Guadix., Peer reviewed

Data used in "Avian sibling cannibalism: Hoopoe mothers regularly use their last hatched nestlings to feed older siblings", Peer reviewed

Additional file 1: Table S1. Sample size of avian nests used to estimate prevalence of extra-pair paternity of the 60 bird species used in the study., Spanish Ministerio de Ciencia, Innovación y Universidades and European (FEDER), Peer reviewed