BOSTON PUBLIC GARDEN 41 



accurate as carefulness and concentration 

 of purpose could attain. 



The years may be compared as to the 

 number of species recorded in each spring 

 migration. In 1900, observation not begin- 

 ning until May 9, fifty species were re- 

 corded; in 1901, fifty-two species; in 1902, 

 sixty-one species ; in 1903, sixty-one species ; 

 in 1904, fifty-five species; in 1905, eighty 

 species ; in 1906, sixty- two species ; in 1907, 

 seventy- four species; and in 1908, eighty 

 species. 



The seasons may also be compared in 

 respect to the aumber of individual birds 

 which sought rest in the Garden. The 

 figures for comparison are obtained from 

 the sum of the daily censuses, and do not 

 take into consideration the fact that many 

 of the visitants remain to a second day and 

 some for several days. The seasons may be 

 regarded as averaging alike in this respect. 

 If we take the fifteen days of May between 

 the ninth and the twenty-third days, both 

 inclusive, which was the entire period of 

 observation in 1900, we obtain these aggre- 



