A fundamental understanding of the distribution and abundance of animals naturally leads to an examination of the factors constraining distribution and abundance. The traditional focus of our research group concerned the quantification of the relationships between animal populations and their food supplies, trying to trace the causal links at the individual level. Whilst maintaining a focus on the individual, i.e. the ‘decision making’ unit of selection that integrates the complex array of social and ecological pressures, the spectrum of factors that mould evolutionary responses, has been expanded to also include energy expenditure, disease factors and the social environment. Our work is done primarily in natural settings, especially those available in the northern Netherlands , and hinges upon detailed behavioural and physiological measurements, as well as fitness measurements to judge the consequences of behavioural variation. When possible, an experimental approach is chosen to determine the causality of relationships between behavioural variation and fitness. We keep an open mind to what new findings and developments in other fields of biological enquiry (such as theoretical biology, ethology, biophysics, genetics, endocrinology, immunology and molecular genetics) have to offer. Indeed, we particularly encourage the use of modern molecular techniques, both to determine genetic relationships between competing and cooperating individuals in a population and to decipher the long-term demographic and genetic histories of populations with a suite of consequences for today’s functioning. Most work is on higher vertebrates, especially birds, but in several cases studies of predator-prey interactions have lead to detailed work on (invertebrate) food organisms as well.
The broad research field of the explanation of the distribution and abundance of animals, even if one restricts the research activities to the higher vertebrates or to birds, cannot be covered by a single research group. Our group necessarily covers only small parts of the huge research arena, but nevertheless incorporates a diversity of approaches that complement and amplify each other. To present the richness of our work, we have chopped up our field of endeavour in a series of nine overlapping research themes:
- Life history strategies
- Population structures
- Sexual selection
- Evolution of Reproduction
- Dispersal Ecology
- Organismal performance in relation to seasonal challenges
- Migration and Immune Function
- Plant-herbivore interactions
- Intertidal foodweb studies
Our main study species are:
- Knots
- Ruff
- Black-tailed godwits
- Seychelles warblers
- Great tits
- Oystercatchers
- Brent and Barnacle geese
