60 PROCEEDINGS OP THE 



on these days lower than it had been before, with frost on the 

 12th. 



The bulk of most of the Warblers, Thrushes, Vireos, Tanagers, 

 etc., went through at this time, and owing no doubt to concen- 

 tration many Golden- winged, Hooded, Wilson's and Bay- 

 breasted Warblers were seen — species that are usually rare. 



The high temperature of May 14th-1.5th is not reflected in 

 the migration record, but that of May 19th produced the last 

 "wave" of the season, the conspicuous species being the 

 Blackpoll and Canada Warblers and Wood Pewee. 



The following cold weather had the efifect of delaying birds 

 that had not already passed through, and holding many 

 stragglers until the middle of June, a week or more after their 

 normal date of departure. 



Comparison with Other Seasons 



In judging whether birds were later than usual in the spring 

 of 1907, we must not be too hasty. It is necessary to be sure 

 what we are basing comparisons upon, and also to differentiate 

 between different portions of the migration. 



Taking the records of thirty-six observers within about ten 

 miles of Philadelphia, we find that Purple Crackles, Robins, 

 Redwings and often Fox Sparrows have their first concentrated 

 flight in February. These species did not move till March in 

 1907, but neither did they in 1905. 



1907. 1906. 1905. 



Purple Grackle, Mar. 3-5 (3)* Feb. 21-24 (15) Mar. 8-U (F. 24) 



Robin . Mar. 13 15 (3) Feb. 20-23 (Jan. 28) Mar. 5-8 



Redwing Mar. 14-16 (9) Feb. 23-24 (4) Mar. 11-16 (9) 



Fox Sparrow Mar. 14-17 04) Feb. 22-24 (20) Mar. 12-16 (12) 



So far as other March migrants go, the season was practically 

 normal, with some very early stragglers during the warm days 

 at the close of the month. 



* Date in parentheses is that of first arrival ; the other is the period of 

 arrival at the majority of stations. 



