Van Oers Group

Van Oers Group

Animal Ecology

'Personality' describes the phenomenon that individuals consistently differ in their behaviour and have limited flexibility to respond to environmental challenges. Our interest lies in describing the causes of these differences and the consequences for individual fitness and population processes in order to better understand the existence and maintenance of individual variation in behaviour.

We study the behavioural, genetic and physiological mechanisms underlying personality expression, their role during development and the consequences for fitness. The ultimate goal is to take these processes that take place on an individual level and measure the consequences on a population level. We do this by combining experiments in our aviary facilities and in phenotyped wild populations. In our studies we make use of long-term data from natural populations, controlled experiments, both in lab and field populations and our genomic toolbox developed in the Songbird Genomics Project. We have a strong collaboration with the Behavioural Ecology group and Animal Breeding and Genomics both at the WUR.

MSc/BSc thesis or internship projects

There are currently openings for student projects (major/minor or research thesis). Contact Kees van Oers
If you have an interest in animal behaviour, behavioural genetics or ecological epigenetics:

At the moment we are searching students for the following project(s):

- The relationship between innovation and habitat quality

- The possible role for great tits in managing Oak processionary caterpillars.

- Cognition in the wild: do species and individuals differ in how smart they are?

- Epigenetic mechanisms underlying personality variation (HAN bioinformatics BSc also welcome)

- Long-term fitness consequences of great tit personality

MSc, PhD or Postdoc opportunities

There are several possibilities for PhDs and postdocs to join the group.
You have an intriguing question that can be answered with our system, and you want to apply for external fundung?

If you are interesting in joining the group please contact Kees van Oers, together with a motivation why you would be interested in conducting your research in our group. If we don't have any open positions in the group, we can seek possibilities for applying for external funding.

Current Projects

DNA Methylation in great tits (PhD project Berncie Sepers; 2018-2022)

Behavioural traits have a stable and a labile component indicating both ian influence of genetic and environmental effects on the expression of these traits. Methylation of cytosines in CpG contexts, particularly within CpG islands, is known to affect gene expression, and is therefore an intersting candidate linking these two aspects of behaviorual traits. Via candidate gene and whole genome appraoches we are unraveling the influences of DNA methylation on the expression of behavioural traits in the great tit.

Main PI and promotor: Kees van Oers, in Collaboration with Koen Verhoeven (Co-promotor - Department of Terrestrial ecology, NIOO-KNAW)

Ecological epigenetics and the brain: the evolutionary consequences of epigenomic modifications in a songbird (PhD project Krista van den Heuvel; 2018-2022)

This unique inter-disciplinary collaboration between three of the larger institutes of the KNAW aims to elucidate the function of epigenetic regulation in the great tit brain to be able to study its role for the evolution of behaviour. Epigenetic mechanisms, such as DNA methylation and histone modification, are key epigenetic mechanisms that can alter gene expression, thereby affecting behavioural variation, both short- and long-term. While we know that epigenetic mechanisms act on different time scales and may be expressed in different tissues or brain regions, an essential gap in our knowledge is: how do epigenomic alterations contribute to fitness variation and what is their role in the evolution of behavioural traits?

Main PI and promotor: Kees van Oers, in Collaboration with Alexander Kotrschal  (Co-promotor - Behavioural Ecology Group, WUR), Chris de Zeeuw and Ingo Willuhn (both NIN-KNAW) and Menno Creyghton (Erasmus MC, former Hubrecht)

Habitat matching or local adaptation: how does habitat quality drive variation in cognitive traits (NWO open competition Postdoc Project - Eva Serrano-Davies; 2020-2024)

Rapid human induced environmental changes have large consequences for the quality of the habitat in which animals are living. An essential question is whether these animals are able to adapt to these changes. Theory predicts that natural selection on cognitive traits, which are broadly defined as traits related to collect, retain and use information, should increase under suboptimal conditions. However, the relationship between cognition and variation in habitat quality has rarely been investigated and it is largely unknown how individuals use their cognitive abilities to adapt to local circumstances. In this project, we will assess the association between variation in habitat quality characteristics and cognitive performance in a long-term study population of great tits (Parus major), a model species for a range of ecological and evolutionary questions. We will test in both a natural and a controlled captive setup, how habitat quality may affect cognitive performance of individuals. By means of three experiments, we aim at inferring the causes and fitness consequences of individual variation in cognitive ability on the potential of individuals to adapt to differences in habitat quality. These results will help us to predict the limits for species to adapt to changes in habitat characteristics, which is especially important in the light of actual ecological impacts of habitat changes worldwide. 

Main researcher: Eva Serrano-Davies; PI - Kees van Oers

What makes innovative animals innovative? VR (Sweden) international Postdoc grant to Utku Urhan (2020-2023)

There are many examples of animals finding new ways to solve problems and using their knowledge in new ways. This is called innovation ability and it varies between species, populations, and even individuals. What then, causes these differences? I propose that this variation occurs due to innovation being a combination of several correlated mental and behavioural processes that, in turn, are affected by environment and genetic factors. I will use three bird species from the Paridae family with different behavioural and cognitive specialisations as my study system. I will use three complementary approaches to test this 1) behavioural and cognitive assays on individuals (correlations of traits with innovation ability). 2) Comparative studies between rural and urban populations (environmental factors), 3) quantitative genetics (do these traits and innovation ability inherited together?). I will control for factors such as hormones, age, sex and social rank of individuals. I will spend the first two years of the project in The Netherlands, in Professor van Oers’ lab (Dept. Animal Ecology, NIOO-KNAW). His lab is uniquely positioned to study wild and hand reared populations with a known pedigree that is 21 generations deep. The last year I will investigate innovation under strictly controlled lab conditions in Professor Brodin’s lab in Sweden (Dept. of Biology, Lund University). This project can add to discussions in evolution of variation between and within species in animals.

Main researcher: Utku Urhan; Supervisor: Kees van Oers and Anders Brodin (University Lund, Sweden)

Former group-members


  • Veronika Laine (KNAW grant; 2019--2020) - 
    Veronika is now Postdoc at the Museum of natural history in Helsinki, Finland.

  • Eveline Verhulst - The role of epigenetic variation in personality expression (NIOO - Strategic Funds 2013)

    Eveline is now Assistent professor in the Entomology Department at Wageningen University & Research (WUR)

  • Alex Baugh - Physiological background of personality (In collaboration with  Michaela Hau 2009-2013)

    Alex is now Assistent Professor in Animal Behaviour at Swarthmore College, USA

  • Nikkie van Bers - High throughput SNP genotyping as a tool for GWAS and QTL studies on personality in an F2 cross population. (2005-2010)

    Nikkie is now Head of Innovation and Application at Genetwister Technologies BV

  • Camilla Hinde (Royal Society grant to CH, 2007)

    Camilla is now Senior Lecturer - Anglia Ruskin University


Nina Bircher: Sexual selection in the wild: male song and female choice in great tits Parus major. (2016-2020)
Nina was supervised by Marc Naguib  (PI and promotor; Behavioural Ecology Group, Wageningen University) and co-supervised by Kees van Oers (Co-promotor).

Lies Zandberg: How is phenotypic variation in great tits maintained by sexual selection? (2013-2018)
Lies was supervised by Camilla Hinde (PI; Behavioural Ecology Group, Wageningen University) and co-supervised by Kees van Oers.
Lies successfully defended her thesis November 2, 2018 and is currently doing a Postdoc at Queen Mary University in London 

Lysanne Snijders: The role of personality in animal social networks (2011-2016)
Lysanne was supervised by Marc Naguib (PI -Behavioural Ecology Group, Wageningen University) and Kees van Oers (Co-promotor).
Lysanne successfully defended her thesis on the 29th of April 2016 (Cum Laude) and is now a Postdoc at the Leibniz Institute of Freshwater Ecology and Inland Fisheries.

Eva Fucikova (thesis). The role of frequency-dependent selection on the maintenance of perosnality variation in the great tit Parus major. 2010. Groningen University.
Eva was supervised by Kees van Oers & Piet Drent (PI) and Marcel Visser was promotor.

Ralf Kurvers 2011. Personality in a group living species; social information, collective movements and social decision-making. Wageningen University.
Ralf was supervised by Herebert Prins & Ron Ydenburg (PI) and Kees van Oers was co-supervisor.