TESTING THE TIME-LIMIT 161 



parents for these and other fancy ducklings, con- 

 demns some Hens as altogether too hot, so that 

 the eggs entrusted to them come out so much too 

 soon that the young are weakly and unsettled, and 

 die off through sheer inability to live. 



The frequency with which eggs of birds have 

 been placed in domestic conditions under other 

 individuals or species has brought out conspicuously 

 the great difference in patience in sitting birds ; 

 Hens and Turkeys will often sit out two periods 

 if compelled or even allowed, while Pigeons refuse 

 to incubate more than a day or two over their 

 limit, and I do not remember any case of water- 

 fowl exceeding their time. However, the Hooded 

 Crow, although one would have thought this 

 cunning bird not easily duped, will, according to 

 Graham in his " Birds of lona and Mull," sit so 

 far over her time when her eggs have been removed, 

 boiled, and replaced by boys, that she is easily 

 captured through the weakness and exhaustion 

 caused by this unnaturally protracted incubation. 



Evidently the Crows are not immune from the 

 extreme mental upset which occurs during the 

 incubation period ; poultry-keepers well know that 

 the most effectual cure for a broody Hen is to 

 place her in a coop with barred floor and supported 

 on legs, for some Hens will sit almost indefinitely, 

 not only on any object they can imagine to be an 

 egg, but even on an empty nest. By making the 

 bird continually perch, however,- the delusion 

 becomes impossible of maintenance, especially if 

 ii 



