From Field Research to the Teaching Classroom: Gull Populations and Mathematical Modelling

Gulls (Laridae) are seabirds and are the focus of long-term research by our group which has monitored their feeding biology, behaviour and population status at various off-shore islands and in urban locations including landfill sites, airports and wetlands. An observed rapid increase in the numbers of breeding Lesser Black-backed Gulls (Larus fuscus) on Cape Clear and Great Saltee Islands was both unexpected and of considerable scientific interest. A detailed programme of research into their breeding biology on Cape Clear Island (Crème, G 1995) did not in itself explain why the L. fucus population there had grown exponentially over a ten year interval, but it did provide parameter values for use in a mathematical model using a difference equation. Mathematical modelling was the only possible approach as the use of a capture-recapture methodology was precluded by the absence of a gull ringing (i.e. banding or marking) programme on the island.Our presentation is the outcome of a collaborative interdisciplinary programme between the Departments of Zoology, Ecology and Plant Science and Applied Mathematics in University College Cork to meet the particular requirements of biology students “wrestling” with a mathematical model. We developed a MS-Powerpoint package for teaching students how to model population change in a gull colony using a classic difference equation. A MS-Excel programme which we developed permits the student to “de-construct” the relevant difference equation and to then reassemble the different mathematical model “components” in a user-friendly way using one integrated package which has an interactive graphical interface to model population changes both numerically and visually. The package is used by both undergraduate and postgraduate students. This is one illustration of the link between Field Research, and the Teaching and Learning of some investigative techniques which employ mathematical models.