Every year they fly thousands of miles between their wintering grounds in the UK and their summer breeding grounds in the arctic. But how do these birds know how much food they need to eat to fuel such incredible journeys?
How do they decide when they have enough fuel to start their marathon flight? What if they hit extreme weather or are blown off course? What if they don’t have enough fuel to reach their destination?
This spring we will be catching and fitting satellite transmitters to each of these birds. Using a unique selection of data analysed by Dr Colin Pennycuick of Bristol University, we will be able to track the birds' fat reserves during their journey to calculate their 'fuel consumption'.
Only when we know how much fuel these birds use to complete their staggering journey, will we know how vital it is to manage and protect their feeding grounds and help them adapt to a changing climate.
Earlier this year we fitted satellite transmitters to three Greenland white-fronted geese and three Svalbard Barnacle geese in Scotland, and three Light-bellied Brent geese in Iceland in early May.
Six of the nine successfully completed their spring migration to their summer breeding grounds. However, we have lost data from two of our Greenland white-fronted geese and one of our Light-bellied Brent geese. Only time will tell whether there is a problem with the transmitters or if, sadly, the three have perished during their arduous journeys.