The scoters prepare for next summer

by Malcolm Ogilvie

In the last two or three weeks, the Common Scoters on the sea loch in front of the house have begun displaying. The breeding season and the annual wing moult is over and now begins the serious business of pair-formation. The next breeding season may be eight months away, but it seems that it is never too soon to make a start. One small flock today, only a hundred yards offshore contained about a dozen males and seven or eight females and, as is quite usual in a party of courting ducks, the males didn't seem to know whether to be aggressive towards each other or perform to the attendant females. Any similarity with humans is, I am sure, completely coincidental.

It was quite windy with white horses on the waves, but this didn't inconvenience the ducks in the least. As I watched, I could see first one and then another male lower its head and neck close to the water and then rush at a rival, skittering many yards over the surface in a rapid charge. Each time the target male dived before the aggressor reached him, whereupon the latter also dived, though what if anything happened under water is unclear, because both birds would surface again with the argument seemingly over. Other males were turning their attentions towards the female, cocking their tails, stretches their necks forwards and upwards and calling with a low piping whistle of one, two or three notes. These are remarkably far-carrying. I had no difficulty hearing them in the wind, while on a calm day I can hear them clearly when the courting party is well over a mile distant.

When several males are performing together there is an almost continuous 'piu piu piu piu' as they strut their stuff, vying with each other in their attempts to attract a mate. Suddenly, the whole small flock started splashing and rushing, males and females together. Then equally abruptly all 20 or so birds dived together, bobbing up some seconds later like black corks. That seemed to be some sort of climax, because things quietened down thereafter and the birds started what looked like ordinary diving for food.

It is no secret that a small number of pairs of Common Scoters breeds on Islay, nesting on small islets in freshwater lochs, or sometimes in dense vegetation on the banks. However, there are always many more scoters on the sea during the breeding season than we have nesting pairs. Last summer there were up to 50 present in June and July, which is many more than the handful of breeding birds. It is possible they are immatures as scoters don't breed until they are two or three years old. In winter, the numbers may reach 250, presumably boosted by birds that breed in Iceland and winter down the west side of Britain.

This, though, is only a tiny fraction of the British wintering population. As was reported in the latest Wildfowl and Wetlands Trust magazine, over 25,000 were found by aerial surveys last winter spread between Liverpool Bay and Carmarthen Bay. This included a previously unknown wintering area several miles offshore from Blackpool, where 10,500 birds were found in the vicinity of a large area of shallow sandbanks. There is clearly still much to discover about this often overlooked sea duck. I count myself fortunate in being able to watch even small numbers of them from the house more or less throughout the year.

More feature articles