Now even the birds are Europeans
by Paul Cormacain
WALKING along the sea front we expected to see seagulls. Perhaps some waders might be about, then creatures like pied wagtails, perhaps a small flock of hungry starlings, all sorts of birds can turn up at the beach.
But nothing that we expected was there, only a flock of hooded crows. They seemed to be enjoying themselves, there must have been food there, for they seemed to be eating all the time. Had they chased the other birds? Was the food they were eating only crow food, not suitable for other breeds? Was this section of beach designated `hoodie beach'? Were there signs up in bird language saying'hoodies only'?
These questions led me to do some research into the hoodies when we got home. I learned something about crows, and was amazed there is always something new to learn. And a small piece of humility set in.
In the older books, the carrion crow was a bird, and the hooded crow was a bird. They had different sections, different scientific names, and were two distinct breeds. Then as the books became more modern, more research showed up, folk became more knowledgeable, and the consensus changed.
The carrion crow and the hooded crow are now one and the same, and it has nothing to do with geographical location. Hooded crows used to live in Ireland and north west Scotland, while carrion crows lived in southern Scotland, Wales and England. Not any more.
The carrion crow used to be Corvus corone corone, and the hooded one was Corvus cornix cornix. Now the carrion, aka the hooded crow, is Corvus corone. Are you following this? Good. So now we have the European crow.
The next time you see a hooded crow, just call it a European crow.
I remember talking to a Geordie expert on birds, he works for the National Trust here, and he used to tell me about carrion crow sightings here. Must remember to tell him to call the bird a European crow in future.
The hooded crow and the carrion crow are easy to tell apart, but they are a single species now! They are just two forms of the European crow. It used to be that they appeared to inter-breed, and great surprise was expressed. Now it is recognised that they interbreed freely because they constitute a single species. Their progeny is fertile, and this constitutes the ultimate test of belonging to the same species.
The so called carrion, an all black bird, inhabits western Europe, while the ex-hoodie, a grey and black bird, lives in eastern and northern Europe. They come into contact along a narrow corridor starting in eastern Ireland, embracing the Isle of Man, extending through Scotland, Denmark, central Germany and Austria, and following the southern slopes of the Alps to the Mediterranean near Genoa in Italy. Every combination of the parental characters is found in this narrow zone of hybridisation. And that includes our old ideas of carrion and hooded crows!
The two forms are thought to have evolved during the last Ice Age, some ten or twelve thousand years ago. Then the European crow separated into isolated populations in the ice-free Iberian and Balkan peninsulas.
These populations were apart long enough to develop distinctive plumage differences, but not separate vocal and behavioural characteristics.
With more time further differences may well have arisen. But then the ice eventually retreated. The two types of European crow expanded to meet in central Europe, and there was no biological incompatibility. So successful inter breeding took place, and still takes place. For are they not the one species?
Now let us travel further east. Near the Yenesei river in central Russia, the all black European crow is again encountered, forming a second hybrid zone which extends for more than 3,000 kms. Thus the grey and black European crow holds a central position, flanked on both east and west by the black European crow.
So if you go down to the beach today, have a look and see what birds are about. Are the gulls there? And what about the waders, and the wagtails, and starlings? Or what about European crows? The large and powerful hooded crows may well dominate the beach, but we must learn to call them European crows!
Coming Events
Thursdays in June - RSPB guided walk at Portmor Lough, at 7pm, details 9049 1547.
Saturdays in June, July - RSPB dragonfly watching at Portmor Lough, details 90 491547.
Saturday 25th, Sunday 26th June - National Trust is hosting a Craft and Food Fair at Rowallane.
Sunday 26th June - Guided Walk at the Umbra Nature Reserve with Wildlife Trust, 2pm, contact Trust on 4483 0282.
Wednesday 29th June - Wildlife Walk around Craigavon
Lakes, at 7.30, details from Oxford Island on 3832 2205.
At Mount Stewart the National Trust is organising a walk to observe
plants which heal. Fascinating. Why not call them on 4483 0282
Sunday 3rd July - National Trust is organising a sea trip to watch birds and seals off County Down. Phone 4483 0282
Ulster Star
13/05/2005
