Dr. Oscar Vedder

DFG Fellow
Institute of Avian Research
An der Vogelwarte 21
26386 Wilhelmshaven

Tel.: +49 4421 9689 16

Research interests

I am broadly interested in behavioural and evolutionary ecology. I work on a diverse set of topics, encompassing sex allocation, sexual selection, phenotypic plasticity, parental effects and natural selection, which together shape individual life histories. Most of my studies are conducted in wild bird populations, in which I complement longitudinal data analyses with specific experiments. This enables me to measure both causal pathways and fitness consequences of natural behaviour. It is especially the integration of methods and ideas from subfields in the study of behaviour, ecology and evolution that I find valuable and strive for.

Overview of my work

For my MSc studies at the University of Groningen (the Netherlands) I investigated sex allocation in Eurasian sparrowhawks (Accipter nisus) with a particular emphasis on the consequences of their extreme sexual size dimorphism. I subsequently investigated sexual selection in blue tits (Cyanistes caeruleus) for my PhD studies, also at the University of Groningen. This project focussed on the potential signalling role of their ultraviolet (UV) crown colouration in intraspecific conflict, and the causes and consequences of variation in their reproductive behaviour (e.g., polygyny, extra-pair paternity, conspecific brood parasitism). Main results were that the signalling potential of their UV crown colouration depended on social and environmental context, and that the proportion of extra-pair offspring declined over the laying order of eggs within a clutch, within individual females. The latter was tightly linked to their incubation profile over the laying phase, suggesting a shared underlying mechanism, and resulted in phenotypic superiority of extra-pair offspring.

After successfully defending my PhD thesis, I obtained an NWO-Rubicon fellowship to study the importance of phenotypic plasticity in great tits (Parus major), and birds in general, at the Edward Grey Institute of the University of Oxford (UK). This revealed that while great tits may be good at adapting to environmental change, by phenotypic plasticity and micro evolution, the slow generation time of longer-lived species make them very much dependent on phenotypic plasticity, leaving their populations vulnerable for continuous change. Working on tits breeding in Wytham Woods also allowed me to do a side project on how predation of great and blue tit fledglings by Eurasian sparrowhawks affects natural selection on tit fledging mass, between and within broods.

From tits I moved to terns, with a von Humboldt fellowship to work in the amazing common tern (Sterna hirundo) research colony of the Institute of Avian Research in Wilhelmshaven (Germany). Their very detailed, long-term, common tern dataset allowed me to investigate between- and within-individual variation in life-history traits, and how this variation shapes their complete life history.

Then, I worked as a NWO-Veni fellow based back in Groningen, but in very close collaboration with the Institute of Avian Research, with the aim to explain between-individual variation (or its absence) in complete life histories. For this I was both interested in ecological factors (e.g., early-life environment) and evolutionary factors (e.g., conflicting selection on parents and offspring). I also used individual measures of telomere length, as a proxy of somatic state, to combine analyses of life-history data with contemporary data. 

Currently, I hold a DFG fellowship and work on the evolution of cascading maternal effects in Japanese quail.