22 A NATURAL HISTORY OF THE DUCKS 



male, are not so different as appears at first sight. Because they extend over a long 

 period and are easily overlooked, they have been misunderstood. 



These general remarks on the subject of moult can be interpreted only as applying 

 to the common northern migrant ducks. We shall see that moult in the tropical and 

 southern hemisphere species is very irregular and ill-defined. In all those species 

 where maturity is not reached the first year (Eiders and Scoters), the plumage 

 changes and moults are still more complex. Then, too, it must not be forgotten that 

 there is a very remarkable amount of variation in the time at which different stages 

 of plumage are reached, even in the same species in similar localities. It is often 

 possible to find forward young of the year in nearly complete maturity by early win- 

 ter, while others, for reasons little understood, may not reach such a stage until late 

 winter or early spring. 



The whole subject of the sequence of plumage and moults in the duck tribe almost 

 deserves a monograph to do it justice. The main facts have been well worked out by 

 Annie Jackson (Meinertzhagen) and E. L. Schibler. 



FLIGHT 

 Who can describe the flight of wild-fowl to one who has never seen it — those great 

 flocks driving through space with perfect order and precision, conveying an idea of 

 power and volition which the scattered, irregular, and rather aimless-looking flights 

 of most of the smaller land birds utterly fail to give us? 



Nearly all ducks are rapid flyers, and there is so much diversity of opinion as to 

 which are the fastest that it is hardly worth while, in the light of our present knowl- 

 edge, to attempt to analyze very deeply. It is safe to say that fifty-five or sixty miles 

 an hour can be attained by many species, and forty to fifty miles is a common speed 

 during migration. Some of the diving ducks certainly fly faster when near the ground 

 than the Mallard-like species. Teals seem to go by at a greater rate than Mallards, 

 but their small size and erratic behavior make this more apparent than real. The 

 great ease with which aeroplanes traveling at not more than seventy-five miles an 

 hour have managed to pick up and kill ducks over the rice-fields of California makes 

 it look as if we should have to revise our earlier conceptions of the velocity of ducks' 

 flight. Recent observations place the speed of ducks while migrating at from forty- 

 four to fifty-nine miles per hour. (Meinertzhagen, Ibis, 1921.) Migrating Canada 

 Geese travel at forty-five miles per hour. 



The river ducks and Teals are far more active and skillful on the wing than the 

 shorter-winged diving ducks, Scoters, and Eiders. But speed and activity on the 

 wing are not confined to the true ducks, for both are well developed in Nettajms 

 (the Goose Teals) , the Carolina and Mandarin Ducks, the Hooded Merganser, and 

 others. The great Steamer Duck of antarctic America, that weighs eight or nine 

 pounds, is apparently on the border-line in losing completely the power of flight. 



