FURTHEK INFORMATION WANTED. 103 



QUESTIONS UPON INCUBATION. 



The precise period of sitting in various species is 

 recorded in only a few instances, and ought to be 

 observed with care, together with an attempt to as- 

 certain what vicissitudes of weather and neglect the 

 eggs are able to survive, whether such misfortunes 

 shorten or prolong the time of sitting, and whether 

 the eggs of diiFerent species vary in respect to hardi- 

 hood. 



Whether there is, or is not, a regular relation 

 between the size of the bird and the length of the 

 incubation necessary to hatching; or, between the 

 character and locality of the nest or any other out- 

 ward circumstances and the same period, might be 

 brought out by a series of such observations, an(| 

 would prove an important addition to ornithological 

 lore, tending to make clearer the influences which 

 act for and against the perpetuation or welfare of a 

 species. Perhaps, also, it will aid us to answer 

 the question why one species, which to all appear- 

 ances has as fair a chance in life as another similar 

 one, should be so much less numerous in representa- 

 tive individuals than its fellow. For e:^ample, why 

 should a great disparity in numbers exist between the 

 yellow-rumped warbler {Dendroeca coronata) and its 



