Naturalised Barnacle Goose census

Save the date

Our first census is taking place on Saturday 18th to Sunday 19th February 2023.

Volunteers will be out counting geese at their designated site(s) during the weekend, but we welcome all other sightings too, to help us build a clearer picture of the mid-winter distribution of the naturalised population and their numbers.

Coordinated census

Three populations of Barnacle geese occur in the UK, two of which are entirely migratory, one originating from Svalbard and the other from Greenland. The third population, the smallest is the naturalised population resident in the UK throughout the year, predominately in England with smaller numbers also occurring in Wales and Scotland. This population is regularly monitored through the Wetland Bird Survey (WeBS), and the long-term trend clearly shows a rapid increase in numbers since the 1980s, in particular since the mid-2000s. The population’s size was estimated to be 4,400 individuals, which is over 60% higher than the previous estimate of 2,700 when assessed in 2011.

Despite flocks of naturalised birds being found at sites across the UK, and although the population is regularly monitored through WeBS, much remains unknown about the seasonal movements and demography of this population. The absence of such fundamental information, such as data on movements, survival and mortality has hindered efforts to understand the demographic causes of the observed increased in population size.

To deliver up to date information on the demography of the naturalised population, the Waterbird Colour-marking Group have initiated a new study which includes the colour-marking of individuals, collecting information on breeding success, survival and mortality and we hope to coordinate the first coordinated census of the population.

Aim of the census

To our knowledge no previous coordinated effort has been organised to count this population of geese. The study therefore aims to look at the following:

  • To carry out two coordinated counts, one in February 2023 and another in autumn 2023. By carrying out two counts, we hope to be able to compare both to assess potential increase in numbers between the two counts. The idea is that the autumn count will be undertaken before any movements occurs to the UK from migratory populations such as those from Svalbard, Greenland and Continental Europe. The mid-winter census (February 2023), could well give us some indication to the numbers of birds potentially arriving from other overseas populations and joining the naturalised population.
  • To undertake a coordinated assessment of the 2023 breeding season.
  • To encourage those out counting to look for colour-marked birds, since the efforts of the group has seen an increase in the number of colour-marked individuals in the population (see here).


Using information from County Bird recorders, WeBS and e-Bird we have produced a list of sites that will need covering to ensure the census is as complete as possible. We have begun the process of enlisting help from local counters, bird watchers and ringers to assist with the census. The census will also rely heavily on local knowledge. Counting methodology has been sent to all those involved in the census.

If you know of a flock of Barnacle Geese and would like to enquire whether this flock is already included within the census, please do get in touch –

Recording breeding success
Age assessment methodology will be available in due course.

Looking for colour-marked birds
Please try to check each bird within the flock for colour-marks. Sightings can be submitted to our online data submission portal, where on submission of a sighting you will be provided with a history of each bird and a map of its movements.

Submission of census data
A data entry submission form has been created (see above) and is now live and ready to accept counts. Paper forms are also available for those counters who do not have access to the internet. Please contact Kane Brides (see below) to request.

On completion of the censuses and after data analysis, we will aim to write up the results for submission to British Birds and the results will also be made available to all who participated.


Please direct all enquires relating to this project to Kane Brides at

Find out more

Find out more about the wider project looking at naturalised Barnacle Geese on our website using the links below.

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