In a collaborative project with the Bean Goose Action Group, since 2012 several Taiga Bean Geese have been caught by WWT at the Slamannan Plateau, near Falkirk, and fitted with GPS tracking devices to help explain their migratory routes through the spring and autumn staging areas and locate the summer quarters of the Scottish Bean Goose flock.
Over recent years, the movements of these geese have provided us with a detailed picture of their migration, daily movements and information on their feeding and roosting sites. Understanding the daily movements and migration route of Scotland’s only regular flock of Bean Goose in relation to proposed industrial developments is essential for safeguarding this important population. Discovering important stopover locations on their spring migration and their breeding grounds has filled a huge gap in our understanding of the life cycle of these geese.
During spring migration this year, the movements of some of the tagged geese provided a remarkable insight in to how risky migration can be and provided us with information on migration strategies and how the geese can adapt to inclement conditions. WWT’s Carl Mitchell explains:
”On the morning of 6 February, four GPS-tagged Bean Geese left Slamannan (half way between Glasgow and Edinburgh) a little after dawn, at about 06h30 and headed east out into the Firth of Forth. By noon, Tag 30 was over half way across the North Sea, and by midnight, it had made landfall in west Denmark. Location data from Tags 27 and 29 indicated a different fate. The birds had passed just to the south of the Isle of May at 09h24 and appeared to take a more northerly course than Tag 30.
Winds in the North Sea at that time were strong easterlies, providing an unwelcome headwind into which the geese were flying. At 18h00, the geese were nearly half way across the North Sea, but the wind had strengthened by then. The geese battled on but had to decide whether to wait and then push on (as Tag 30 had done) or abandon their crossing. The geese turned around.
The next location point placed the geese just to the south east of Fair Isle at 18h00 on 7 February. They made landfall on Stronsay (Orkney) by midnight and then moved to north mainland (Orkney) on 8 February. Up to this point, although the location data were not synchronised, it is highly likely that three of the tagged geese (Tags 10, 27 and 29), were flying together, possibly within a larger flock of Bean Geese. Despite alerting birdwatchers on Orkney, the flock could not be located and so there is no record of the number of geese involved in the abandoned migration.
From this point, Tag 10 separated from the others. Tags 27 and 29 then moved to Caithness, arriving by noon on 9 February. The following morning (10 Feb) they headed due south and, remarkably, arrived back at Slamannan by 18h00. The roundabout journey had taken approximately five days.
The pair then attempted a second crossing leaving Slamannan on the afternoon of 20 February. A more southerly route was taken across the North Sea and the geese made a successful crossing, making landfall in Denmark by midnight later that day. During this time, Tag 10 had remained on Orkney. It spent 10 days near Loch of Swannay, before moving south to fields near Stromness on 17 February. It was seen together with local Greylag Geese and was on its own. On 2 March, it left Orkney at dawn and headed east, crossing the North Sea and arriving on the southern coast of Norway at 14h00. Having rested, it then resumed its journey, leaving southern Norway at dawn on 3 March and arrived in north west Denmark by 09h00, where it re-joined the rest of the Scottish flock.
The movements of the tagged geese provided a remarkable insight into migration strategies, and raises important questions. Some adults made it through (Tag 30), some abandoned the crossing, returned to the starting point and tried again (Tags 27 and 29), and one goose remained in the area to where it had been windblown and tried again from there. It confirms that large birds such as geese can abandon a long sea crossing and make it safely back to land to try again. It also highlights how rare birds can turn up in odd locations and successfully re-orientate, even on their own (Tag 10). But perhaps most surprisingly, it confirms that birds once displaced by a storm event, they can re-orientate and head back to their original starting location and try again (Tags 27 and 29). We assume that neither Tag 27 and Tag 29 had visited Orkney before, yet, within a day, they had plotted and flown a course due south and arrived back at Slamannan to try again”.
Thanks to Carl Mitchell for this news item.