Models of swan population dynamics and growth - a review

Abstract

A model of Mute Swan breeding success is developed which depends on the females’ abilities to gain weight in early spring. It is parameterised with data from Groningen, Netherlands. The model predicts that many swans may be able to achieve similar annual cygnet production over a wide range of incubation periods, and that their actual behaviours might thus be appreciably constrained by factors formerly thought to be of minor importance. Sensitivity analysis suggests these predictions are robust to two critical but poorly known factors: weights of females in late winter; changes in food quality and availability during early spring. The implications of the model to additional aspects of Mute Swan ecology and to the migratory arctic breeding swans are discussed.