The Birds' Calendar 



in all places, the spring observations are al- 

 ways likely to be considerably in excess of 

 those in fall. As before remarked, a few spe- 

 cies seem to take a more inland route in one 

 direction than in the other, and among those 

 that follow the same route at both seasons there 

 seems to be more lingering by the way in 

 spring. 



Still another difference, making the identifi- 

 cation of species far more difficult in fall, is the 

 intermixture of the young on their first journey 

 southward, in their immature and somewhat in- 

 determinate plumage. In some cases the males 

 do 'not attain " full dress " until the third year, 

 and probably never until the second, and in 

 the process of development the young of both 

 sexes strongly resemble the less characteristical- 

 ly marked female. 



Again, besides being more easily observed in 

 the leafless shrubbery and trees of spring, they 

 are more approachable at that season than at 

 any other time. The white-throated sparrow, 

 so shy in summer as often to elude the most 

 careful search, and revealing itself only by its 

 song, is very unsuspicious in the spring. The 

 instinct of all animals impels them to be espe- 

 cially on their guard during the season when 

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