Abstract

A census in February 2023 showed that the population of naturalised Barnacle Geese Branta leucopsis in Britain and Northern Ireland was an estimated 5,800. This is a 456% increase since the only previous census, in 1991. Naturalised Barnacle Geese were found at 98 sites, with most birds present in England and smaller numbers in Scotland, Wales, Northern Ireland and the Isle of Man. Given such a rapid increase in this naturalised population, we recommend increased future monitoring, including colour-ringing.