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Quantifying the urban gradient: A practical method for broad measurements.
Gábor Seress, Ágnes Lipovits, Veronika Bókony & László Czúni; Landscape and Urban Planning 131: 42-50, 2014.

The opening page of the freeware.

The opening page of the freeware.

In this study we describe and validate an easily feasible method to quantify the degree of landscape urbanization. This method relies only on freely available imagery from GoogleMaps, and ranks the study areas along an urban-rural gradient based on major land-cover characteristics. We propose this newly developed application as a useful tool for broad measurements of urbanization and we also provide a download link to our freeware and user’s guide.

Sex-biased survival predicts adult sex ratio variation in wild birds.
Tamás Székely, András Liker, Robert Freckleton, Claudia Fichtel & Peter Kappeler; Proceedings of the Royal Society B 281: 1788, 2014

African fish eagle

African fish eagle pair: raptors are among the most parental care role-specialized birds.
photo: Tamás Székely

Social role specialization promotes cooperation between parents.
Zoltán Barta, Tamás Székely, András Liker & Freya Harrison
American Naturalist 6: 747-761, 2014.

How and why does natural selection favour the evolution of cooperation between individuals? We used evolutionary simulations to show that when individuals need to cooperate in two different ways, selection for individuals to specialise in only one behaviour makes the evolution of cooperation much easier than expected.

Mating rollers photo: Csaba Daróczi

Mating rollers
photo: Csaba Daróczi

Divorce and Infidelity Are Associated with Skewed Adult Sex Ratios in Birds
András Liker, Robert P. Freckleton & Tamás Székely
Current Biology, 24: 880–884, 2014.

see in the news: Mail Online

  • Divorce rates are higher in birds with female-biased sex ratios
  • Infidelity is more common in male-biased species
  • For both sexes, the frequency of polygamy is related to adult sex ratio
  • The sex ratio is a strong driver of many aspects of mating behavior


Sparrow eggs Photo: Ivett Pipoly

Sparrow eggs
photo: Ivett Pipoly

Multiple aspects of plasticity in clutch size vary among populations of a globally-distributed songbird
David F. Westneat, Veronika Bókony, Terry Burke, Olivier Chastel, Henrik Jensen, Thomas Kvalnes, Ádám Z. Lendvai, András Liker, Douglas Mock, Julia Schroeder, P. L. Schwagmeyer, Gabrielle Sorci & Ian R. K. Stewart Journal of Animal Ecology 83: 876–887, 2014.

We participated in a collaboration with several colleagues around the world, led by David Westneat, to study how clutch size in house sparrows varies with date and attempt order within and among populations. Surprisingly, the seasonal decline in clutch size was steeper in populations with longer breeding seasons, and the among-individual variation of this slope was similar across populations.

urban sparrow

Every day a new challange. Are you prepared? photo: Balint Preiszner

Necessity or capacity? Physiological state predicts problem-solving performance in house sparrows.
Bókony, V., Lendvai, Á.Z., Vágási, I.Cs., Pătraş, L., Pap, P.L., Németh, J., Vincze, E., Papp, S., Preiszner, B., Seress, G. & Liker, A., Behavioral Ecology 25:124-135 2014.

Innovations help animals adapt to new or altered environments. But what makes individuals innovative? Our study shows that good health is important. Problem solving success in novel food-extracting tasks was promoted by superior physiological condition in a context-specific manner in house sparrows. Birds with more antioxidants solved easy tasks faster, while birds with less stress hormones were faster in solving and learning a difficult task.

Sparrow chicks - 12 days old

Sparrow chicks – 12 days old
photo: Ivett Pipoly

Effects of Extreme Weather on Reproductive Success in a Temperate-Breeding Songbird.
Pipoly, I., Bókony, V., Seress, G., Szabó, K. & Liker, A. PLoS ONE, 8(11), 2013.

Warm weather favors chick growth in house sparrows but extremely hot days have the opposite effect, according to our latest research.

Smart birds stress less

Unflappable. The Australian raven (Corvus coronoides) has a relatively large brain and relatively low levels of a stress hormone. photo: Daniel Sol

Do smart birds stress less? An interspecific relationship between brain size and corticosterone levels
Lendvai, Á.Z., Bókony, V., Angelier, F., Chastel, O. & Sol, D., Proceedings of the  Royal Society B 280: no. 1770, 2013.

Being smart may pay off when your life is at risk.Vertebrates from fish to humans respond to dangerous situations by secreting ‘stress hormones’ that help the body cope with the current challenge. This reaction is very general though and may be physiologically costly too, so sometimes it may be better to recognize and avoid the threat.

Read more on the story at “Science NOW“, “” or “

Environmental factors shaping the distribution of common wintering waterbirds in a lake ecosystem with developed shoreline.
Pap, K., Nagy, L., Balogh, C., G-Tóth, L. & Liker, A., Hydrobiologia 716: 163-176, 2013.

Fewer invited talks by women in evolutionary biology symposia.
J. Schroeder, H. L. Dugdale, R. Radersma, M. Hinsch, D. M. Buehler, J. Saul, L. Porter, A. Liker et al., Journal of Evolutionary Biology 26: 2063–2069, 2013.

Why care? Inferring the evolution of complex social behaviour.
Székely, T., Remeš, V., Freckleton, R.P. & Liker, A., Journal of Evolutionary Biology 26: 1381–1391, 2013.

Male pheasant-tailed jacana on thenest, photo: Ghulam Rasool

Male pheasant-tailed jacana on the
nest, photo: Ghulam Rasool

The evolution of sex roles in birds is related to adult sex ratio
A. Liker, R.P. Freckleton & T. Székely, Nature Communications 4:
Article number 1587, 2013

Read more on the story at BBC News