Barnacle Goose

Project summary

Birds colour-marked

Sightings received

Year project started

Colour-marks used
Blue leg ring, 3 white characters (letter, number, number) on one leg with BTO metal on other leg. Some birds may have a colour ring above or below the metal
Yellow leg ring, 3 black characters (letter, number, number) on one leg with BTO metal on other leg.
White neck collar, 3 black characters (letter, number, number). BTO metal ring on a leg


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 is currently estimated to be 4,400 individuals, which is over 60% higher than the previous estimate of 2,700 when last assessed in 2011.

Despite flocks of birds being found at sites across the UK, and although the population is regularly monitored through WeBS, much still remains unknown about the movements and demography of this naturalised 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 this population, we will be starting colour-marking birds in England in order to collect data on movements, survival and mortality.

Naturalised Barnacle Goose Census 2023

In February 2023 we’ll be working with volunteers around England, Wales and Scotland to carry out a census to better understand the mid-winter distribution of the naturalised population and their numbers. Find out more on the link below.

Want to know more?
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