Icelandic-breeding Goose Census
Counts of the Greenland/Iceland Pink-footed Goose and Iceland Greylag Goose populations began in Britain in 1960. The census initially involved one coordinated count in November at various key locations throughout the country, in order to provide national population estimates for both species. They were timed to take place after the geese had arrived back in Britain, with the Greylag Geese usually arriving later than the Pink-footed Geese.
In 1990, a second coordinated count, in October, was introduced, following evidence from Scotland that suggested that November was no longer the best time to count Pink-footed Geese (Newton et al. 1990). This count has remained part of the census, though peak counts of Pinkfeet have been found to occur in either October or November, depending on the timing of their departure from Iceland.
During the 1990 census, a number of ‘goose count coordinators’ were recruited to help improve the organisation of the census in particular areas, and coverage in Britain was much improved. The survey was also extended to include some parts of southwest Iceland, representing areas known to hold large numbers of geese in the spring.
In 1998, Ireland was included in the census for the first time and in 2001, it was extended further to include other sites in the wintering range, namely the Faroe Islands and Norway, along with further sites in Iceland. Thereafter, the census became known as the Icelandic-breeding Goose Census (IGC).
With the increasingly late arrival of Greylag Geese to the UK, in 2005 a third coordinated count was introduced in December to determine whether it was a better month in which to count the species. After three winters, an appraisal of the count data indicated that November and December were the best months in which to count Greylag Geese. However, as of the 2014/15 season there was no longer a requirement to undertake a count in December.
Although Pink-footed Geese have also been arriving later, their migration has not advanced sufficiently for December to be a suitable month in which to count this species. Although peak numbers have increasingly occurred in November, October still provides the peak count in around half of all years.
Spring counts of both populations have also been undertaken periodically to determine the distribution of geese at this important time of year, when they are feeding vigorously to store nutrient reserves for successful migration and breeding. These counts do not provide a way of censusing the whole population, but it does identify the key sites being used by the geese, thereby providing a means of ensuring these sites are as protected as possible.
Aim and methods
The aim of the IGC is to determine the population size of the Greenland/Iceland Pink-footed Goose and the Iceland Greylag Goose, and provide information on the distribution of the geese during the autumn and early winter, thus identifying important sites for each species.
The IGC is an annual survey that consists of two coordinated counts: one in October and one in November. Sites holding Pink-footed Geese are covered in both October and November, whilst those at sites holding Greylag Geese are mainly covered in November. Spring counts of both populations are undertaken every three years.
Counts are primarily of roosting birds which are ideally conducted at dawn as birds leave the roost, but dusk roost counts are made at some sites. Exceptionally, daytime counts of feeding birds are made in areas where roost sites are poorly known or inaccessible, or too few counters exist in order to provide coordinated coverage of roost sites.
An additional September count is undertaken at some sites to determine the number of British Greylag Geese present before the arrival of the Icelandic migrants. The results of these counts can then be deducted from the winter counts in order to estimate the number of Icelandic birds present.
Results from the Icelandic-breeding Goose Census have been presented in various reports and can be downloaded from our ‘Reports and newsletter‘ page.
Counters interested in taking part in the IGC must be able to identify Pink-footed and Greylag Geese and have reasonable experience of counting birds; for sites holding large numbers of geese, observers must be confident in their ability to estimate large numbers accurately.
In Britain, survey sites are mainly located in Scotland, and in northern (Lancashire/Cumbria) and eastern (Norfolk to Northumberland) England. In Ireland, the census covers Northern Ireland and the eastern counties of the Republic of Ireland.
The survey consists of one coordinated count per month in October and November on pre-determined dates. A count is also undertaken periodically in the spring. An additional September count is undertaken at some sites.
If you would like to participate in the IGC please contact WWT’s Monitoring Unit.
Dates of the census are posted on our GSMP network page, where a count form is also available to download
Newton, S.F., .M.V. Bell, A.W. Brown & R. Murray. 1990. Pink-footed Goose numbers at arrival sites in eastern and central Scotland. Scottish Birds 16: 35-36.