WILD DUCKS 157 



the hatch, even though they are set on the ground. They 

 could be set on the ground in a shed, provided the ground 

 under the nest be kept moist. Some breeders of mallards, 

 however, use tiers of nest compartments in hatching-houses, 

 construct the nests of sods, and soak them with a watering- 

 pot each day, which seems to answer the purpose. 



Period of Incubation. I had hoped in my experiments in 

 hatching wild ducks' eggs in camp in the Northwest to learn 

 the exact periods of incubation of the various species. The 

 few incomplete fresh clutches found were shipped East and 

 did not hatch, and those hatched on the spot were all more 

 or less incubated when taken. Careful incubation records 

 of most species are hard to get, but Henry Cook has kindly 

 supplied a good list from records of results on his place at 

 Woodbury, Long Island, New York, as follows: mallard, 

 27 to 28 days; black duck, 26 to 27; wood duck and mandarin 

 duck, 28 to 30; gadwall, 28; redhead, 28; European widgeon, 

 24; shoveller, 22 to 24; all teals, 21 to 23; fulvous and red- 

 billed tree ducks, 26 to 28 days. Wallace Evans, who has 

 hatched thousands of wood ducks, says that the above period 

 for this species is correct. Captain Gates, in his book on 

 mallard breeding, says that the period for this species he has 

 known to vary, according to conditions, from twenty-three 

 to twenty-nine days, but that the average is about twenty- 

 six days. Doubtless there is considerable variation with all 

 species, according to weather, temperature, closeness of sit- 

 ting, and perhaps age of the birds producing the eggs. 



Artificial Incubation. Though the general practice with 

 fanciers is to use hens, there are some who use incubators 

 and brooders. This, in fact, is commonly the method of 

 commercial duck farms, where Pekins, mallards, and others 

 are raised in quantities for market. These species are hardy, 

 eggs are abundant, and it is cheaper on a large scale, even 



