We study animal behaviour, ecology and evolution, focusing on birds as research organisms.
Our fields of interest cover a wide range of topics including social, sexual and parental behaviour and adaptation to environmental changes such as habitat urbanization and climate change.
From our latest research:
Vincze, E., Pipoly, I., Seress, G., Preiszner, B., Papp, S., Németh, B., Liker, A. & Bókony, V.
Urban animals often take more risk toward humans than their non‐urban conspecifics do. However, reduced vigilance toward hostile humans or non‐human predators that pose actual threat may be costly. Thus, urban animals may benefit from showing specific responses to different threat levels. We compared responses of urban and forest‐breeding great tits (Parus major) to familiar hostile and unfamiliar humans as well as one of their common predators, the sparrowhawk (Accipiter nisus). We found that urban birds were more risk‐taking toward both humans and sparrowhawk than forest birds. However, responses to sparrowhawk did not correlate with responses to humans. This suggests that higher risk‐taking of urban compared to forest‐dwelling great tits toward sparrowhawk may be threat‐specific response to lower predation risk rather than a spillover effect of increased tolerance to humans. Furthermore, birds responded similarly to unfamiliar and familiar (potentially dangerous) humans in both habitats. These findings indicate that urban birds may flexibly adjust their risk‐taking to certain, but not all, types of threat.
Ágh, N., Piross, I.S., Majoros, G., Csörgő, T., Szöllősi, E., Parasitology 146: 814–820.
Avian malaria parasites can negatively affect many aspects of the life of the passerines. Though these parasites may strongly affect the health and thus migration patterns of the birds also during autumn, previous studies on avian malaria focused mainly on the spring migration and the breeding periods of the birds. We investigated whether the prevalence of blood parasites varies in relation to biometrical traits, body condition and arrival time in the European Robin (Erithacus rubecula) during autumn migration. Surprisingly we found that these parasites did not affect the body size or condition and showed no sex or age related variance, but the timing of autumn migration differed marginally between infected and non-infected juveniles, so that parasitized individuals arrived later at the Hungarian stopover site. This is either because avian malaria infections adversely affect the migration timing or migration speed of the birds, or or because later arriving individuals come from more distant populations with possibly higher blood parasite prevalence. This delay in timing can affect the whole migration periods, the overwinter survival and perhaps the next breeding success as well.
Sánchez-Tójar, A., Nakagawa, S., Sánchez-Fortún, M., Martin, D., Ramani, S., Girndt, A., Bókony, V., Liker, A., Westneat, D.F., Burke, T., Schroeder, J., eLife 7:e37385.
The status signalling hypothesis aims to explain within-species variation in ornamentation by suggesting that some ornaments signal dominance status. Here, we use multilevel meta-analytic models to challenge the textbook example of this hypothesis, the black bib of house sparrows (Passer domesticus). We conducted a systematic review, and obtained primary data from published and unpublished studies to test whether dominance rank is positively associated with bib size across studies. Contrary to previous studies, the overall effect size (i.e. meta-analytic mean) was small and uncertain. Furthermore, we found several biases in the literature that further question the support available for the status signalling hypothesis. We discuss several explanations including pleiotropic, population- and context-dependent effects. Our findings call for reconsidering this established textbook example in evolutionary and behavioural ecology, and should stimulate renewed interest in understanding within-species variation in ornamental traits.
Végvári, Z., Katona, G., Vági, B., Freckleton, R., Gaillard, J., Székely,T., Liker,A. Ecology and Evolution 13: 6483-6491.
Sex‐biased dispersal is common in vertebrates, although the ecological and evolutionary causes of sex differences in dispersal are debated. Here, we investigate sex differences in both natal and breeding dispersal distances using a large dataset on birds including 86 species from 41 families. Using phylogenetic comparative analyses, we investigate whether sex‐biased natal and breeding dispersal are associated with sexual selection, parental sex roles, adult sex ratio (ASR), or adult mortality. We show that neither the intensity of sexual selection, nor the extent of sex bias in parental care was associated with sex‐biased natal or breeding dispersal. However, breeding dispersal was related to the social environment since male‐biased ASRs were associated with female‐biased breeding dispersal. Male‐biased ASRs were associated with female‐biased breeding dispersal. Sex bias in adult mortality was not consistently related to sex‐biased breeding dispersal. These results may indicate that the rare sex has a stronger tendency to disperse in order to find new mating opportunities. Alternatively, higher mortality of the more dispersive sex could account for biased ASRs, although our results do not give a strong support to this explanation. Whichever is the case, our findings improve our understanding of the causes and consequences of sex‐biased dispersal. Since the direction of causality is not yet known, we call for future studies to identify the causal relationships linking mortality, dispersal, and ASR.
Pogány, Á., Vincze, E., Szurovecz, Z., Kosztolányi, A., Barta, Z., Székely, T., Riebel, K. Behaviour, DOI: 10.1163/1568539X-00003500
Consistent individual behavioural differences (‘animal personalities’) are documented across a variety of animal taxa. Sexual selection, especially assortative mating has been suggested as a possible mechanism contributing to the maintenance of different personality types within populations but little is known about non-random pair-formation with respect to personality traits in unconstrained choice tests. We here tested whether female mating preferences were non-random with respect to male and female neophobia in zebra finches (Taeniopygia guttata), an important avian model of mate choice and animal personality research. Male and female neophobia was assessed by attaching novel objects to birds’ feeders. Females’ mating preferences were tested with randomly assigned, unfamiliar males in a four-way choice apparatus. Females associated most with males with neophobia scores similar to their own. These results provide evidence that mating preferences and personality traits can covary, supporting evolutionary scenarios of assortative mating contributing to the maintenance of personality traits.
Sinkovics,C., Seress,G., Fábián,V., Sándor,K. & Liker,A. Journal of Field Ornithology, 89(2):165-172
In this paper we examined the accuracy and repeatability of estimates of the size of food items from video recordings. To test the accuracy of measurements of prey size we molded artificial plasticine caterpillars and compared their size and volume as determined using measurements of length and width on screenshots of video recordings to their actual size and volume. We also studied within‐ and among‐observer repeatability of measurements of the size and volume of actual prey items delivered to nestlings by adult Great Tits. We found that observers were able to accurately measure prey size and determine volume, with high agreement between the actual size and volume of plasticine caterpillars and the size and volume as determined from measurements made on screenshots from video recordings. In addition, within‐ and among‐observer repeatability were also high. Overall, our results suggest that the size of prey items delivered to nestlings by adults in video recordings can be accurately measured and those measurements, in turn, can be used to accurately determine the volume of those insect prey.
Seress,G., Hammer,T., Bókony,V., Vincze,E., Preiszner,B., Pipoly,I., Sinkovics,C., Evans,K. & Liker,A. Ecological Applications, 28(5):1143-1156
In this paper we studied a tri-trophic system of trees – phytophagous insects (caterpillars) – insectivorous birds (great tits Parus major) to assess how urbanization influences i) the phenology of each component of this system, ii) insect abundance and iii) avian reproductive success. We use data from two urban and two forest sites in Hungary, collected over four consecutive years. Despite a trend of earlier leaf emergence in urban sites there is no evidence for an earlier peak in caterpillar abundance. Thus the earlier breeding of urban bird populations is not associated with an earlier peak in caterpillar availability. We also found striking differences in the seasonal dynamics of caterpillar biomass between habitat types with a single clear peak in forests, and several much smaller peaks in urban areas. Caterpillar biomass was 8.5 – 24 times higher in forests compared to urban areas during the first brood’s chick-rearing period. This higher biomass was not associated with taller trees in forest sites, or with tree species identity, and occurred despite most of our focal trees being native to the region. Urban great tits laid smaller clutches, experienced more frequent nestling mortality from starvation, reared fewer offspring to fledging age, and their fledglings had lower body mass. Our study strongly indicates that food limitation is responsible for lower avian reproductive success in cities, which is driven by reduced availability of the preferred nestling diet, i.e. caterpillars, rather than phenological shifts in the timing of peak food availability.
Ágh, N., Kovács, Sz., Nemesházi, E. & Szabó, K. Magyar állatorvosok lapja, 140: 47-59.
Defining the sex of individual birds can be crucial for scientific studies and captive breeding, as well. However, many bird species (and almost all nestling) can only be sexed via molecular methods. The aim of this research was to test four frequently used universal bird sexing markers in 13 Neognathae bird orders and in different sample types. These markers (P2/P8, 2550F/2718R, CHD1-i16 and CHD1-i9) amplify fragments of intronic regions of the CHD1-Z and CHD1-W genes. Our results confirm the universality of these primer pairs in most avian orders, but their application needs some consideration.
Haematospirillum and insect Wolbachia DNA in avian blood
Hornok, S., Ágh, N., Takács, N., Kontschán, J., & Hofmann-Lehmann, R. Antonie van Leeuwenhoek, 1-5., DOI: 10.1007/s10482-017-0961-0, 2017
In this study, blood samples of 259 Acrocephalus spp. warblers were molecularly analysed for Anaplasmataceae and Rhodospirillaceae based on PCR amplification of 16S rRNA gene fragments. We founded the first molecular evidence for the occurrence of Haematospirillum jordaniae in the blood of any vertebrate other than human. Another bird blood sample yielded a Wolbachia sequence, closely related to a moth endosymbiont. This is the first finding of insect Wolbachia DNA in the circulatory system of birds, which can be explained either by the inoculation of wolbachiae by blood-sucking vectors, or passing of Wolbachia DNA from the gut into the blood of this insectivorous bird species.
Climate-driven shifts in adult sex ratios via sex reversals: the type of sex determination matters
Bókony V., Kövér Sz., Nemesházi E., Liker A., Székely T. Philosophical Transactions of the Royal Society B: Biological Sciences, 372: 20160325, 2017
Sex reversals whereby individuals of one sex develop the phenotype of the opposite sex occur in amphibians, reptiles and fish. Warming of global climate predicts that such sex reversals are becoming more common. We show using theoretical models that XX/XY and ZZ/ZW sex-determination systems can respond differentially to temperature-induced sex reversals. Analyzing data from the literature, we find that the adult sex ratio in natural amphibian populations shifted towards males in ZZ/ZW species over the past decades, but did not change in XX/XY species. Our results highlight the need for understanding the interactions between genetic and environmental sex-determining mechanisms.
Effects of capture and video-recording on the behavior and breeding success of Great Tits in urban and forest habitats
Gábor Seress, Ernő Vincze, Ivett Pipoly, Tamás Hammer, Sándor Papp, Bálint Preiszner, Veronika Bókony & András Liker. Journal of Field Ornithology, 88(3): 299-312, 2017
We studied the effects of both capturing, weighing and measuring, and taking a blood sample, and the presence of video-cameras on the behavior of male and female Great Tits breeding in urban and forest habitats. Using a 2 x 2 block design, we compared the behavior and breeding success of parents that either were or were not captured on their nests a few days before behavioral observations, and of parents that either were or were not habituated to the presence of a concealed video-recorder mounted on nest boxes. We found no significant effects of habituation to the camera on bird behavior, but males captured in their nest boxes were more vigilant and hesitated longer before entering nest boxes, and also had slightly lower provisioning rates than males that had not been captured. Captured females also tended to be more vigilant than non-captured females, but their provisioning rates were not affected. In males, capturing also influenced the behavior of their non-captured mates. We found no difference in the effects of capture in urban and forest habitats, and our treatments also had no effect on the mass, size, and survival of nestlings until fledging. Our results suggest that, for Great Tits, being captured results in sex-dependent behavioral effects that can last for at least several days.
Does urbanization affect predation of bird nests? A meta-analysis
Ernő Vincze, Gábor Seress, Malgorzata Lagisz, Shinichi Nakagawa, Niels J. Dingemanse & Philipp Sprau. Frontiers in Ecology and Evolution, DOI: 10.3389/fevo.2017.00029
Urbanization can affect interspecific interactions such as predation on bird nests. Using a formal meta-analytical approach, we carried out a systematic literature review to test whether predation on natural and artificial bird nests increased or decreased with habitat urbanization. We found that the effect was highly heterogeneous among studies, due to contrasting results between studies that used artificial nests and those that used natural nests. For artificial nests, survival rate tended to decrease with increasing urbanization, whereas for natural nests, survival was higher in more urbanized habitats. This discrepancy suggests that the direction of the relationship between urbanization and nest predation is likely to depend on the methodology of the study.
Innovative females are more promiscuous in great tits (Parus major)
Veronika Bókony, Ivett Pipoly, Krisztián Szabó, Bálint Preiszner, Ernő Vincze, Sándor Papp, Gábor Seress, Tamás Hammer & András Liker. Behavioral Ecology, DOI: 10.1093/beheco/arx001, 2017
We found that innovative great tit females are prone to cuckold their mates. Innovative problem solving can be important to animals for survival and reproduction in nature, yet we found no evidence that females mated to males with poor problem-solving performance compensate for poor male quality by obtaining superior genes for their offspring from other males via cuckoldry. Instead, females’ infidelity increased with their own innovativeness.
Status signalling in male but not in female Eurasian Tree Sparrows Passer montanus
F Mónus, A Liker, Z Pénzes, Z Barta. Ibis 159: 180-192, 2017
We investigated the outcomes of aggressive encounters in foraging flocks of free-living Tree Sparrows, and assessed whether throat patch size and measurements of body size predicted fighting success. We found that male throat patch size predicted fighting success against both male and female opponents. However, female throat patch size did not correlate with fighting success against either sex. Among the morphological traits studied, wing length was the best predictor of fighting success in females. Our findings suggest a status signalling function of throat patch size in males but not in females.
Problem-solving performance and reproductive success of great tits in urban and forest habitats
B Preiszner, S Papp, I Pipoly, G Seress, E Vincze, A Liker, V Bókony.
Animal Cognition, 20: 53–63, 2017
Success in problem solving, a form of innovativeness, can help animals exploit their environments, and recent research suggests that it may correlate with reproductive success. Innovativeness may have a greater positive effect on fitness in more urbanized habitats. We tested this idea in great tits by measuring their problem-solving performance in two tasks. Urban pairs were significantly faster problem-solvers in both tasks. In one of the tasks positive fitness consequences were found, though irrespectively of urbanization. Neophobia, sensitivity to human disturbance, and risk taking in the presence of a predator did not explain the relationships of problem-solving performance either with habitat type or with reproductive success. The reproductive benefit of innovativeness in great tits is similar in urban and natural habitats, implying that problem-solving skills may be enhanced in urban populations by some other benefits or reduced costs.
Habituation to human disturbance is faster in urban than rural house sparrows
Ernő Vincze, Sándor Papp, Bálint Preiszner, Gábor Seress, Veronika Bókony & András Liker. Behavioral Ecology 27: 1304-1313, 2016
Urban birds need to reduce their fear from humans to tolerate their presence. We show that urban house sparrows in the field have shorter flight initiation distances from humans than rural ones, but in captivity they initially show similar fear from humans. However, urban sparrows show faster habituation, i.e. decrease their fear response to repeated human disturbance faster. This difference may play a role in why certain birds exploit urban habitats better than others.
The evolution of parental cooperation in birds.
Vladimír Remeš, Robert P. Freckleton, Jácint Tökölyi, András Liker & Tamás Székely. Proceedings of the National Academy of Sciences USA 112: 13603–13608, 2015
Parents in many animal species care for their offspring. In some species males care more, in other species females care more, whereas in still other species the contribution of the sexes is equal. Using the most comprehensive analyses of parental care to date, here we show that parents cooperate more when sexual selection is not intense and the adult sex ratio of males to females is not strongly skewed. However, the degree of parental cooperation is unrelated to harshness and predictability of the ambient environment during the breeding season. These results suggest that several parental strategies may co-exist in a given set of ambient environment.
The genetic sex-determination system predicts adult sex ratios in tetrapods.
Ivett Pipoly, Veronika Bókony, Mark Kirkpatrick, Paul F. Donald, Tamás Székely & András Liker. Nature 527,91–94, 2015
Recent theoretical and empirical work shows that adult sex ratio (ASR, proportion of males in the population) has a major influence on pair bonds, mating systems and parental care, although the causes of ASR variation have remained obscure. Here we show for the first time that ASR is predicted by the type of genetic sex-determination system in amphibians, reptiles, birds and mammals: the heterogametic sex is underrepresented in the population. Using novel population-genetic models, we also explore various genetic mechanisms that can mediate the effects of sex-determination systems on ASR.
Sex differences in parental care: Gametic investment, sexual selection, and social environment.
András Liker, Robert P. Freckleton, Vladimir Remeš &Tamás Székely. Evolution 69: 2862-2875, 2015
Using detailed behavioural data of nearly 800 birds, we confirm theoretical models proposing that parental sex roles are predicted by sexual selection and the social environment, but are unrelated to gametic investment of the sexes.
Using the BirdTree.org website to obtain robust phylogenies for avian comparative studies: A primer.
Rubolini, D., Liker, A., Garamszegi, L.Z., Møller, A.P. & Saino, N. Current Zoology 61: 959-965, 2015
Comparative studies require accounting for shared evolutionary history. The online publication of the phylogeny of extant bird species (www.birdtree.org) now allows biologists to rapidly obtain phylogenetic trees for any set of species to be incorporated in comparative analyses. We discuss methods to use BirdTree tree sets for comparative studies, either by building a consensus tree that can be incorporated into standard comparative analyses, or by using tree sets to account for the effect of phylogenetic uncertainty.
Does innovation success influence social interactions? An experimental test in house sparrows.
Preiszner, B., Papp, S., Vincze, E., Bókony, V. & Liker, A., Ethology 121: 661–673, 2015.
Individuals may benefit from the presence of an innovative group-mate because new resources made available by innovators can be exploited. In this study we conducted an experiment to investigate whether individuals behave differently towards their innovative and non-innovative flock-mates in the house sparrow. Our experimental results suggest that some common social interactions are not influenced by the apparent problem-solving ability of the group-mates, however birds may use subtle cues to to assess the problem-solving ability of their companions.
A comparison of problem-solving success between urban and rural house sparrows.
Papp, S., Vincze, E., Preiszner, B., Liker, A. & Bókony, V. Behavioral Ecology and Sociobiology 69: 471-480, 2015.
Behavioral flexibility is an important component of adaptation as it can help animals to exploit new or diverse habitats. Due to the abundance of novel objects and resources provided by humans, urban environments may select for better problem solving skills in wild animals. To test this idea, we compared the performance of house sparrows from urban and rural habitats in four novel problem solving tasks during which they had to acquire food from different feeders. These results demonstrate that problem solving success shows both individual consistency and context dependence, and whether or not urban individuals are more innovative across various situations.
Habitat urbanization and its effects on birds.
Seress, G. & Liker, A. Acta Zoologica Academiae Scientiarum Hungaricae 61: 373-408, 2015
This review focuses on the bottom-up and top-down regulation of urban bird communities. In our work we also discuss and illustrate the mechanisms which generate and uphold the changes in urban avian communities, and affect birds’ physiology, behaviour, morphology and breeding success.
Does urbanization facilitate individual recognition of humans by house sparrows?
Ernő Vincze, Sándor Papp, Bálint Preiszner, Gábor Seress, András Liker & Veronika Bókony; Animal Cognition 18: 291-298, 2015
Individual recognition of humans may be beneficial for animals living in an anthropogenic environment, but little is known about how this ability changes along the urban gradient. In this study we captured house sparrows from differently urbanized habitats and manipulated their experience (hostile or not) associated with humans with different faces (masks). Surprisingly, we found that rural sparrows adjusted their behaviour more to the percieved dangerousness of the person than their urban conspecifics.