BULLETIN No. 36 59 



Of the species rt-corded on Ma\' 8, 1899, 20 were not seen 

 this year, and therefore seventeen recorded this year were not 

 seen in 1899. It is interesting to notice that this difference of 

 species lies almost wholly in the unusual species and that the 

 difference in the seasons seems to have little effect. This list 

 is smaller chiefly because less time could be given to the work, 

 not because some of the later migrants had not yet arrived. 

 The species which are common to all three of the years number 

 88. Starting with this number for a basis one might reason- 

 ably expect to record more than a hundred species on/any 

 day between the 5th and 20th of May, assimiing favorable 

 weather. 



In the absence of actual experiment to prove it, one may 

 not be allowed to say that any untried day was a better day 

 for birds than those tried, but judging from appearances and 

 from the appearance of fields and woods on May i8th, 1 would 

 say that that was the most favorable day of the year. It 

 was not possible for me to prove it, however. The later 

 migrants were just in and the north bound ones which had comie 

 ejrlier were still with us. What the probabilities for the 

 unusual species would have been only actual field work could 

 demonstrate. 



It is true that we have exploited this "All Day " May day 

 far more than any other "All Day " of the year, chiefly because 

 there is a certain interest which attaches to the largest horizon, 

 but the reader is not to conclude from this that our attention is 

 focused upon this May day work. The horizon taking continues 

 during the whole ytai so far as other duties will permit. When 

 sufficient material has been collected it is proposed to tabulate 

 the results of this work with a view to determining the status 

 of the bird population for each week of the migration periods 

 and for each month during which there is little or no change in 

 the bird population. What other deductions may follow from 

 this work time will show. 



In the list which follows the species which were common on 

 the 9th have a C following the name. These followed by a 

 number indicate the number of individuals seen during 'the 

 day : 



