THE BIRDS OF NEW JERSEY. 17 



MIGRATION OF BIRDS. 



[From Mr. Witmer Stone's "Birds of Eastern Pennsylvania and New Jersey."] 



The spring migration in the vicinity of Philadelphia 

 begins early in February with the arrival from farther 

 south of scattered bunches of Robins, Bluebirds, Purple 

 Grackles, and a few other species which often occur in 

 small numbers during the winter. 



About the middle of the month, on the first clear, 

 spring-like day when the temperature rises to 60 or TO 

 degrees F., a well marked wave takes place. Purple 

 Grackles, Red- winged Blackbirds, Robins, Bluebirds and 

 a few Flickers are the principal species, the Grackles 

 being the most numerous. The greater part of these 

 early migrants seem to pass farther north. 



From the time of occurrence of the first well marked 

 wave, the species above mentioned continue to pass in 

 increasing numbers during favorable weather, but there 

 is usually no other decided wave until about the middle of 

 March. 



During this month, in addition to the species already 

 mentioned, the principal migrants are the Meadowlark, 

 Pewee, Field Sparrow, Fox Sparrow, Cowbird, Dove, 

 Canada Goose and Killdeer Plover, together with a 

 few Yellow-bellied Sapsuckers, Savanna Sparrows, Vesper 

 Sparrows, Myrtle Warblers and Rusty Grackles. None 

 of these birds, however, arrive at least in abundance 

 before the middle of the month. 



Up to April 1 no migrants have been recorded in the 

 records that we have examined which do not occur occa- 

 sionally in winter, either at Philadelphia or a little far- 

 ther south in New Jersey, except the Canada Goose and 

 Chipping Sparrow, which latter species has been once or 

 twice noticed during the last week of March. 



