158 PROPAGATION OF WILD BIRDS 



if losses are somewhat larger. Different workers claim to 

 hatch with machines from 60 to 75 per cent, of the eggs set, 

 or about 80 per cent, of the fertile eggs. In such cases they 

 usually have large brooding-houses and all facilities. Where 

 it is a matter of operating single outdoor brooders, with a 

 moderate number of ducklings, it is safer and far less trouble 

 to use hens. 



There is no question, however, that wild ducks' eggs hatch 

 very well in incubators. On two expeditions to Northwest 

 Canada to experiment with ^y'''^':^Jz~\\ I had each year a 

 hatch with C}T3her s incubatOia ui 92 per cent, of the total 

 number of eggs, including about a dozen species. These 

 were eggs of wild ducks gathered in the marshes. Nearly 

 all were fertile, owing to the vigour of the wild stock, and in 

 most cases every egg of the set hatched, or all but one. The 

 young were reared in brooders. It was necessary to manage 

 in this way, as in the wilderness it was impossible to secure 

 hens, particularly broody ones. 



My method, which is the usual one, was to run the ma- 

 chine at 103°, raising to 104° during hatching. The eggs 

 were gathered in all stages of incubation. When a set was 

 pipped, the eggs were usually transferred to a separate ma- 

 chine with higher temperature. Some sets, however, 

 hatched in the general machine at 103° and the young 

 seemed to do just as well. The eggs were well sprinkled 

 daily with tepid water which felt slightly warm to the hand, 

 were turned, and were aired till the temperature felt neutral 

 when the egg was placed against the eye. Two towels 

 dripping wet with warm water were at this time placed 

 in the bottom of the machine. 



The German method used by Ludwig Seidler, similar 

 toothers as to temperature, in the incubation of ducks' eggs 

 uses all possible moisture, as near to saturation of the air as 



