Waders Imitate Each Other

13-04-2012   Current distribution models for social animals are inadequate because they do not take into account that species do not just compete with each other but may also attract one another. This is one of the results Eelke Folmer presents in his PhD thesis. Folmer studied 'self-organization' by various species including foraging waders on the Wadden mudflats. Folmer will defend his PhD thesis 'Self-Organization on Mudflats' at the University of Groningen on 20 April 2012.

An ecologist, watching foraging birds on the mudflats through binoculars, cannot help wondering why, for example, a large group of knots is at one specific spot rather than another; and why the curlews are so far apart? Soil samples, observations, and surveys all provide a wealth of data. But finding ecological patterns and regularities in all these data is quite a task. Computer simulations, spatial statistical models and structural equation models may help in sorting out the information and revealing processes of self-organization.

Self-organization - a process taking place at system level as a result of repeated interaction and reactions by the various elements - forms the basis of many cultural and natural phenomena. The development of hypes and the behaviour of financial markets are examples of cultural phenomena that are characterised by sudden and large-scale changes. These dynamics arise when individuals that are part of these systems, depend on each other, pay attention to one another and imitate each other.

When less information is available, it gets more difficult to make wise, independent decisions, and as a consequence individuals increasingly imitate one another. Foraging waders also have to cope with incomplete information and mutual dependence. They imitate the behaviour of their own kind and thus display what we might call 'hypes' at every low tide: imitation when selecting foraging spots on the mudflats. Copying the behaviour of other waders pays off, because food is available in a limited number of spots. This explains why knots can be seen in such large groups on the mudflats.

The current foraging models, which are based on competition and on factors unrelated to the birds (such as the availability of food), fail to explain the distribution of foraging spots. Individuals also attract each other because the presence of their own kind suggests that food is available. In addition, it reduces the risk of being caught by a bird of prey. Using simulations, Folmer has developed and tested a method for statistically estimating social attraction resulting from self-organization. Biologists can now more easily take into account the effect of 'hypes' when accounting for the distribution of social species.

Eelke Folmer (Sneek, 1976) studied Biology at the University of Groningen in the Netherlands and completed his PhD at the Department of Animal Ecology at the Centre for Ecological and Evolutionary Studies (CEES). His PhD project was funded by the University of Groningen, and much of the practical work was carried out at the Royal Netherlands Institute for Sea Research (NIOZ). Folmer is currently employed as a post doc at NIOZ.