48 PROCEEDINGS OF THE 



The early May migrants were usually a day or two earlier 

 than the average; the White-eyed and Red-ej^ed Vireos, Balti- 

 more Oriole and the Black-throated Blue Warbler making the 

 earliest bulk movements recorded for these species. 



Most of the later May migrants were late, owing, to the cooler 

 rainy weather that prevailed from May 4 to 8. The Chat, 

 Rose-breasted Grosbeak, Indigo Bird, Olive-backed Thrush, 

 Yellow-billed Cuckoo, Hummingbird, Wood Pewee, Black-poll, 

 Kentucky, Magnolia and Canada Warblers were all later than 

 the average by from one to four days. 



The dates of bulk arrival for the 64 species discussed above 

 will be found in the last column of the Philadelphia schedule 

 pp. 49-52. The date is that upon which the species had arrived 

 at one-half of the stations at which it was recorded, disregard- 

 ing entirely the last quarter of the records, which represent in 

 the majority cases late or erroneous dates. 



For example the House Wren was recorded as arriving as fol- 

 lows ; at one station on April 16th, three on the 19th, two on 

 the 20th, one on the 21st, four on the 23rd, five on the 24th, 

 five on the 25th, five on the 26th, two on the 27th and one on 

 May 1st, at twenty-nine stations in all. Discarding the last 

 quarter of these records as probably later than the bird actually 

 arrived we have twenty -two left, and the bird had reached eleven 

 of these (one-half) by April 23 which we take as the date of 

 bulk arrival. 



