A discrete model for the growth and spread of the Scottish populations of red squirrels ( Sciurus vulgaris ) and grey squirrels ( Sciurus carolinensis )

Abstract In this article, a model, discrete in space and time, is developed to describe the growth and spread of the Scottish populations of red squirrels ( Sciurus vulgaris ) and grey squirrel ( Sciurus carolinensis ). The initial state for the model is designed using a large dataset of records of sightings of individuals of both species reported by members of the public. Choices of parameters involved in the model and their values are informed by the analysis of this dataset for the period 2011-2016, and model predictions are compared to records for the years 2006-2019.