Spatio-temporal variation in cat population density in a sub-Antarctic environment

We used the walked-line transect method for estimating the density of cats and coefficients of variation of density estimates in 4 contrasted sites on the main island of Îles Kerguelen between 1998 and 2000. Density estimates varied from 0.44ǂ.15 cats per km² to 2.42ǂ.23 cats per km² according to site and period. Coefficient of variation of density estimates ranged from 11.92% to 34.76%. The line transect method was, therefore, an efficient method for monitoring the density of the cat population in a sub-Antarctic environment characterised by short vegetation. Our results suggest that cat population size at the main island of Îles Kerguelen (the total number of cats expected is around 7,000) is much lower than previously thought.