DELAWARE VALLEY ORNITHOLOGICAL CLUB. 



47 



Averaging these results we get as our average for this vicinity, 

 April 22, while the average of computed bulk-arrival dates for 

 ten years is April 23. The average date of arrival at these ten 

 stations for the nine species or birds selected is as follows, while 

 at the bottom is given the resulting average arrival date for this 

 vicinity and the average of the bulk-arrival dates computed for 

 each year. 













bier. 



^ 



1 















u 







^ 



^ 











1 



O 



3 



o 



a 

 2 



-1^ 



a 



a 





1 



c3 



i 

 > 



IS 



2 



§ 





A^ 



^ 



PQ 



o 



W 



S 



O 



o 



Beverly and R \ 



F. 25 



M. 26 



A. 21 



A. 23 



A. 26 



A. 26 



A. 29 



M. 1 



M. 2 



Moorestown . . 



23 



26 



21 



22 



22 



26 



30 



1 



3 



Swarthmore . . 



27 



17 



22 



22 



27 



28 



28 



A. 29 



A. 30 



Lansdowne . . 



25 



19 



22 



24 



25 



26 



29 



29 



28 



Media 



29 



17 



22 



21 



27 



23 



29 



30 



24 



Ardmore and H ' 



29 



20 



22 



23 



27 



30 



M. 1 



29 



30 



Westtown. . . 



24 



18 



22 



23 



27 



29 



A. 29 



29 



30 



Kennett Square. 



23 



22 



23 



21 



M. 2 



28 



30 



M. 1 



M. 4 



Concordville. . 



21 



16 



19 



22 



A. 30 



26 



28 



A. 28 



A. 30 



George School . 



21 



21 



24 



20 



25 



29 



30 



28 



M. 1 



Average . . . 



Feb. 25 



Mar. 20 



Apr. 22 



Apr. 22 



Apr. 27 



Apr. 27 



Apr. 29 



Apr. 29 



Apr. 30 



"Bulk Arrivals" » 



Feb. 28 



Mar. 21 



Apr. 23 



Apr. 22 



Apr. 26 



Apr. 28 



Apr. 30 



Apr. 30 



Apr. 30 



' Bancocas. 



* Haverford. 



' Average of " Bulk Arrivals." 



The case of the Purple Grackle is undoubtedly influenced by 

 the early stragglers which have wintered not far away, and which 

 often appear before the regular migratory flight and make the 

 average of ''first arrival" at many stations earlier than it really 

 should be. In the other species the dates are the same in three 



