A rare Kumlien’s gull has been seen at Littlehampton.
I have been down to the seafront to claim this once-in-a-lifetime twitcher’s ‘tick’, but was unsuccessful.
The bird was apparently with other gulls over the waves, but was picked out by quick-sighted ornithologists a few days before.
It is practically unknown here and only in recent years has it been accepted as a subspecies of the Iceland gull. That particular visitor is seen now and then along the Sussex shores.
But not Kumlien’s. So how do ornithologists tell the two apart? With difficulty.
Kumlien’s gull has not such pure white primary wing feathers, the long ones that act like propellers and do most of the pushing.
Otherwise, both birds are overall greyish white with no black wingtips as most gulls have. There are 50 shades of grey in seagull feathers.
You have to notice such things to be successful tracking down these birds.
There are also 12 different species of gulls in Sussex that are fairly commonly seen all the time and this makes the business of identification a challenge.
But it does not end there.
All gulls change plumage twice a year, to breed, and then to rest.
Young gulls have different plumage to their parents and may take four years to obtain the full mature dress.
So you could end up with 48 permutations.
Add breeding plumage for adults and this shoots up to 60.
Take this picture, for instance, I took of gulls on the seafront of Westward Ho! last autumn.
It could have been taken at Littlehampton. Could you identify them all? Of course.
This is an easy one because they are the commonest gull of all on Sussex shores and you see them every day over the city, the towns, and way inland on the floods and the ploughed fields.
They are all black-headed gulls.Yes, they have lost their black heads which were the breeding uniforms. They retain a small spot behind the eye which now distinguishes them.
But what is the bird in the foreground?
It has brown speckles on its back which the others do not.
That shows it to be a young one. All have red beaks and legs so they are not common gulls, which have yellow legs and beaks.
It is a juvenile, a bird of the year. If gulls were not so common, people would flock to see them.
As it is, the only people who ever look at them are bird watchers and glider pilots.
My brother John, who competed in many national and international gliding championships, knew how to watch seagulls.
They always found the thermals first. Sir Peter Scott who competed against John (and beat him by a whisker to become national champion) often told how he had followed lesser black-backed gulls in flight, so gaining valuable seconds in cross-country flights.
He would have been able to identify a Kumlien’s gull without any bother, even when sitting on his parachute in the cockpit.
He probably did a painting of one, too.