6 BULLETIN 936, U. S. DEPARTMENT OF AGEICULTUEE. 



represent the actual number of birds produced from this marsh that 

 are available to sportsmen there and elsewhere. 



HABITS AND ACTIVITIES AFTER THE NESTING SEASON. 



In the course of studies in this region it was learned that the 

 great marshes in the delta of Bear River not only offer a favorable 

 breeding ground for many pairs of ducks, but also that they are 

 even more important as a refuge and feeding ground for a much 

 larger number of birds after these are freed from family cares in 

 other regions. To maintain themselves in condition, all species of 

 birds must renew their bodily covering of feathers at least once 

 each year, while many forms molt partially or entirely at shorter 

 intervals. This usually is a gradual process, as only a few feathers 

 drop out at one time and are replaced by new ones. One or two 

 feathers fall in either wing at approximately the same time and 

 more are not lost until the first ones are partly grown. By this 

 continuous renewal the powers of flight of the ordinary bird are 

 not seriously hampered and it is able to feed, fly about, and evade 

 its enemies as usual. 



In wild ducks and geese, however, the process is entirely different. 

 In common with grebes and rails, the ducks and other anserine birds 

 drop all the feathers of the wings and tail at about the same time, 

 and for a period of four or five weeks are wholly unable to fly. At 

 this time they must have access to large marsh areas where they 

 may find an abundance of food without exposing themselves unduly 

 to the attacks of enemies. Many thousand ducks from other areas 

 gather in the Bear River marshes each season for this purpose, 

 greatly augmenting the numbers of those that breed there. 



In all the species of ducks that frequent this area in summer, 

 except the ruddy duck, the males nearly always desert their mates as 

 soon as the complete set of eggs has been deposited and incubation 

 has begun. During three summers spent on Bear River the writer 

 saw many hundreds of broods of wild clucks, but, except in the case 

 of ruddy ducks, not more than ten instances were observed where 

 drakes accompanied the young. The male ruddy duck, like the 

 Canada goose, usually stays with the female until the ducklings are 

 well grown, and it is common to see one at the head of a brood 

 of dusky young, swimming with chest and neck puffed out and tail 

 spread. Occasionally a male gadwall, shoveler, or mallard may 

 accompany a female and her brood, but such occurrences are rare. 



After the pairing season the' drakes begin to join in flocks, and 

 large bands of these males gather to feed and rest on the great open 

 bay-. At this time they are in bright, showy plumage, but early 

 in summer a change takes place. The body feathers are replaced by 

 a plain dull plumage more or less resembling that of the female, 



