Gannets over Flanders

Flanders Moss NNR

OK so the picture is very poor, almost to the Darren Hemsley standard of wildlife photography, but it shows gannets flying over Flanders Moss. Gannets are ocean birds that nest mostly on off-shore islands and range hundreds of miles across the sea looking for the fish they feed on so why are these birds over one of the furthest NNRs from the sea?

Gannets over Flanders Moss is actually a more common occurrence than you might think and most years I see them, usually in between August and October. Bu this year they have been seen almost everyday. The nearest gannetry where these birds almost certainly come from is Bass Rock in the Firth of Forth. This is the worlds biggest gannetry of Northern gannets with 75 000 pairs. The youngsters that this colony produces have a number of challenges to reach adulthood. First they have to leave the rock and this they do by leaving their parents,  almost falling off their ledges and gliding down onto the sea. This is because they are so fat they can barely fly. This fat layer keeps them going until they can then learn to fly and only once they can fly can they then learn to feed themselves by diving from height into the sea to catch fish. Next they need to migrate because gannets head south for the winter and first year gannets tend to travel the furthest and will spend the winter months off the coast of west Africa (Senegal). With Bass rock producing perhaps 50-60 000 youngsters each year most head south down the east coast of Britain. But as with every population there is variation of behaviours. A few birds have been found to actually travel in the opposite direction and go north and then west around the top of the country. And an unknown number take the middle ground and move from Bass Rock up the Firth of Forth and then cut across the narrow waist of Scotland to the Clyde and then out into the Atlantic. These are the birds I am seeing and they have all been brown all over, the colour of all first year gannets.

Last week I saw birds on nearly everyday – just small numbers between 1 and 5. And it seems they may have several routes across Scotland as there is a paper in Scottish Birds that describes them flying over Falkirk and probably along the route of the Forth and Clyde canal. But during the Peatland Conference held at Balloch when staring out of the window rather than concentrating on the presentation on greenhouse gas emissions of restored peatlands I noticed 3 gannets circling over the Lomond Shores. These are ones that probably came over Flanders, likely along the route of the A811 to Loch Lomond and then down the River Leven to the sea. Little has been written about this overland migration by an ocean loving bird that usually will do anything to avoid flying over land. And it begs a few questions:

– how do they navigate – do they smell the sea? can they see it by gaining height?

– why in groups? – nearly everytime I have seen birds in group – 1 year a group of 30+ went over.

– why head to the west side of the UK?

It will be 5 years before these birds will start breeding, mostly likely at the colony where they were hatched, so Bass Rock, so they have a lot of flying yet to do.

If anyone knows more I would be very interested in hearing from them.

Reference.

Taylor, I.R. – 1977 – Overland passage of Gannets from Forth: Scottish Birds 9 – 298.