38 A NATURAL HISTORY OF THE DUCKS 



under special permits from the United States Biological Survey. This matter has 

 been discussed from time to time in reports of the Chief of the Bureau of Biological 

 Survey and in United States Department of Agriculture bulletins. 



In taking up the different species, mention will be made of grain-feeding habits 

 wherever this seems to be of economic importance. We must hope that methods 

 only mildly destructive will be worked out to prevent economic loss, and these, of 

 course, will differ according to the nature of the crop and the kinds of wild-fowl that 

 feed upon it. A certain type of bomb exploded during the night has already proved 

 quite successful in California. 



BEHAVIOR IN CAPTIVITY 

 There is a general impression in this country that almost any species of wild duck 

 can be bred under fence, and that large numbers are being so reared on farms and 

 preserves and in municipal gardens. A certain game-breeders' journal has fostered 

 this idea. Now, if we get down to cold, hard, and disagreeable facts, we shall find 

 that only a half-dozen species can be classed as among those that lay readily in con- 

 finement, and the great proportion of ducks can either not be reared at all, or only 

 with great difficulty, as a sort of avicultural "stunt." In other words, they are in 

 the same category as our Ruffed Grouse and Prairie Chickens. I do not include in 

 the above generalization those places where ducks are kept on large ponds in almost 

 natural conditions, many of them with full wings, and particularly those ponds located 

 where there is no bad winter freeze-up. With such fortunate conditions many kinds can 

 be tempted to lay that would rarely or never build nests in artificial enclosures or small 

 crowded pools, where all natural food, both plant and animal, is soon exhausted. 

 Then there is a large class of ducks that simply do not keep healthy in captivity, and 

 are short-lived when deprived of wild food. Such are Shovellers, Scaups, Canvas- 

 backs, Golden-eyes, Eiders, and the fish-eaters. Ruddy Ducks only live a week or 

 two. Some of the rarer tropical and Australian ducks have received so little atten- 

 tion from aviculturalists that we hardly know what they might do. But the mere 

 fact that a species apparently flourishes does not mean that it is easily bred. Thus 

 the Tree Ducks live to a green old age, without as a rule any sexual instincts showing 

 themselves. The two easiest ducks to breed are Mallard and Muscovy, but even 

 Mallards will often refuse to lay the first spring after they have been trapped and 

 pinioned. Carolina Ducks are next in order. Egyptian Geese are readily bred, when 

 one has the space; as are Ruddy Sheldrakes, and Paradise Sheldrakes. Most of the 

 Mallard-like ducks are seldom kept, because they are not particularly ornamental, 

 but the Indian Spot-bill responds readily in confinement, and so does the Australian 

 Duck. 



The Pintail must be classed as fairly easy to rear, and the Blue-winged Teal, if 

 one can winter it successfully, is not a rare breeder. For the rest, it must be said that 



