“Local Raptors, or are they?” by Ed Drewitt

Tuesday 9^th September 2008

We’re all now familiar with the idea of birds migrating: we have Swallows visiting in summer and Fieldfares visiting in winter. But somehow we tend to think that raptors are here all year round. The first picture in Ed Drewitt’s talk showed a flock of literally hundreds of Chinese Goshawks on migration, demonstrating that raptors are migrants too.

After a general introduction about migration, Ed pointed out that, since Sparrowhawks feed off smaller birds, they naturally need to migrate to follow their food supply. Songbirds such as Fieldfares and Redwings breed in Scandinavia in the summer, but migrate to Britain and western Europe in winter. So, the Sparrowhawks follow them on their journey.

By contrast, Buzzards are sedentary. Buzzards were formerly confined to the west of Britain, particularly following the effect of DDT on their eggs a few decades ago. Since they don’t tend to move very far, it has taken them a quite long time to spread back across the country. Now they are regulars in places like Norfolk.

For birds like the Peregrine falcon, some populations migrate a long way, while other birds only move quite short distances. Birds in Finland have been found to migrate in winter to France, Spain, or even Morocco, “leapfrogging” over other birds which remain more local, for example moving between Holland and Belgium.

Owls also migrate over long distances, for example Short-eared Owls that winter here may come from Scandinavia. Currently, there is a lot of controversy about some Eagle Owls that are breeding in the wild in northern England. While some people think that the owls are birds that have escaped from captivity, Ed pointed out that they could be wild owls that originally arrived from continental Europe. Eagle Owls eat a wide range of other birds, including other owls and even Peregrines. Ed wasn’t sure how they catch the Peregrines - presumably they do not manage to out-fly them.

Merlins are one type of falcon that is a more obvious migrant - we tend to see them in winter in places like Exmoor. On the other hand, Honey Buzzards visit us for the summer. They are not seen very often, but quite large numbers were counted in 2000, when adverse weather in the Channel held up their autumn migration - so perhaps there are more of them breeding here than we realise.

Ed finished his talk with a section on Ospreys. In this region, we regularly see Ospreys on the Exe estuary at migration time. Chew Valley Lake is another good place to spot them. Quite a number of pairs of Osprey now breed in Scotland and a few in northern England. But, we also get Ospreys from Scandinavia passing through Britain. They fly all the way through France and Spain, to spend the winter in west Africa, in places like Senegal. Some of the Ospreys are now being tracked using satellites, and information about their progress is shown on the web.

To summarise, Ed showed us that, our local raptors are often not at all local. Along with many other birds, they migrate large distances to follow the weather and their food supply. As he told their story, he threw in many interesting nuggets of information - only a few of which made it to this report.

Richard Swinbank