The excitement of the East coast sea-bird migration: Is it happening unseen over Cambridge?
Nature Notes | Bob Jarman discusses autumn sea-watching.
Wait for an autumn northerly wind and you will see them: from Hunstanton cliffs to Cley beach, in the promenade shelters at Weybourne, Sheringham, and Cromer to Southwold and Landguard - the sea watchers peering through their telescopes.
Autumn sea watching is one of the most exciting aspects of birdwatching. You just do not know what you will see next. Northerly winds push migrating seabirds onto our east coast. These seabirds breed on the northern isles and sub-tundra moors and are migrating south to the coasts of West Africa. Some even cross the Atlantic to the coast of Argentina for the winter.
If you see a strong passage of gannets then you know there’s more to find and for me the skuas are a real thrill. They are thugs and bullies, chasing gulls and terns, following every evasive move until they force them to disgorge their most recent meal. The skuas then swoop down to catch the vomit in mid-air or scoop it up from the surface of the sea; partly digested and pre-warmed!
The great skua, or bonxie, is a real villain. I have seen it raid auk colonies on steep cliffs for guillemot chicks. I once saw a bonxie take a small rat from Lerwick harbour in Shetland and swallow it whole. Arctic skuas are more elegant! They are serious kleptoparasites of sea terns. I once saw a party of 12 pomarine skuas – heavyweight versions of arctic skuas – fly along the dunes at Holme and look me straight in the eye as much to say, “What are you looking at, mate!”
But the skuas are in trouble. As Arctic tern breeding colonies fail due to a decline in small fish to feed on so do the skua populations. The UK breeding population of Arctic skuas has declined by 70 per cent in the last 20 years.
There is an enigma about the skua migration in north Norfolk in the autumn. You would expect these migrating seabirds to fly east and around the coast following the sea line into the English Channel and then the Atlantic to their wintering grounds. But they don’t, they fly west into The Wash!
At Foul Anchor, the most northerly village in Cambridgeshire, next to the River Nene, parties of skuas have been seen flying south and inland. In the 1980s and 1990s large flocks of skuas were seen flying high over Milton. Can it be there is a cross-country overland migration of these seabirds following the southerly trajectories of the Cam and Nene river valleys?
We know that in spring, parties of returning skuas round Malin Head in Donegal and fly up the Scottish coast, then take an overland short cut through the Great Glen and Loch Ness to the North Sea and onwards to the northern isles and Scandinavia. Is a similar over-land migration happening above Cambridge in the autumn, but too high to be seen easily?
In October 2019, staff at St John’s College found a dead long-tailed skua – the rarest of the skuas - near Queens Road. It had probably been killed by a nocturnal peregrine falcon strike. This seabird was on an overland southward migration.
There are more than skuas on a good sea watch. Shearwaters and petrels, and this year a brown booby, auks such as guillemots and eiders and scoter ducks in numbers.
Years ago, my friend Pete and I travelled together to Holme-next-the Sea, on a Lambretta scooter. On one bitterly cold day I was driving and wearing two of my father’s ex-RAF coats. When we arrived I was so cold I could not stop shivering. We settled down to sea watch and Pete picked out a Leach’s petrel - a top bird to find! Every time I looked to locate it I shivered so much I couldn’t keep still, and every time I raised my binoculars it dropped behind the crest of a wave.
It disappeared from view. I didn’t see it then, and still have never seen one!