128 DWIGHT 



moult earlier than those at its northern. I fancy that this has 

 something to do with the great individual variation we see in 

 immature birds the following summer. A species that might 

 raise two broods at the south would perhaps raise but one at 

 the north and we might suppose the older birds to be more 

 vigorous. It is apparently the case with species raising two 

 broods everywhere. Young birds show variable vigor and pre- 

 sumably the highest plumaged are the oldest and the ones most 

 likely to assume at the postjuvenal moult feathers that in the 

 younger would not be donned until the prenuptial period. 



Preponderance of Young in Autumn 



There is another matter which comes in naturally at this 

 point. The vexed question why young birds are obtained in 

 the autumn in such overwhelming abundance as compared with 

 adults has never been solved. Various explanations have been 

 offered but none of them seems adequate. Several causes 

 probably contribute to make adults in fall plumage so rare in 

 collections and I have a new one to add which I believe is an 

 important factor in the case. It is simply that the old birds 

 take better care of themselves and the young most frequently 

 fall victims to our powder and shot. Anyone who has chased 

 a family of Towhees (Pipilo crytliropJitliabuiis) along a hedge row 

 will be prepared to admit that it is the parents who skip along 

 at the head of the procession with surprising alacrity. In the 

 autumn do we not find adult Wood Pewees (yContoptis virens) 

 and Scarlet Tanagers {Piranga eiytJiromelas) almost inaccessible 

 at the very tops of the tallest trees ? If anyone doubts whether 

 old birds take good care of themselves let him use his gun with 

 this idea in view before the woods and fields are invaded by a 

 host of passing migrants from the north. Just as soon as the 

 young of our summer species reach a stage when they no longer 

 need to be fed by their parents, the latter cannot be lured by 

 the most seductive squeakings one can muster which earlier 

 would have thrown them into a high state of excitement and 

 remonstrance. It is the young that are attracted by the sounds 



