30 BIRDS OF THE NEW YORK CITY REGION 



(April 17-April 25) 



Bittern Blue-headed Vireo 



Night Heron \/ Black and White Warbler 



Clapper Rail ^^XlMyrtle Warbler 



v/Virginia Rail V' Black-throated Green Warbler 



V Towhee *v Louisiana Water-thrush 



N/Barn Swallow v' Brown Thrasher 



While it is most exceptional for one of these species not to 

 arrive in April, they are the only ones which can be counted 

 upon. In six years out of ten, however, there is a third move- 

 ment between April 25th and 30th, bringing the majority of 

 the following species : 



(April 25-April 30) 

 v/Green Heron Purple Martin 



Greater Yellowlegs Cliff Swallow 



v/Spotted Sandpiper Bank Swallow 



Broad-winged Hawk J Rough-winged Swallow 

 Whippoorwill Yellow Warbler 



V'Chimney Swift N^Iouse Wren 



May is the star month of the year for the bird-lover. The 

 migration becomes more marked and continuous. A vast 

 horde of birds flood the countryside and pour overhead at 

 night, their calls coming to us from the sky. A rise in 

 temperature and a light southerly wind is apt to bring a great 

 "wave. " As many as a dozen new species will arrive over- 

 night. A drop in temperature, cold rain, or strong northerly 

 or easterly winds are equally certain to bring a lull in migra- 

 tion. Five distinct groups of species can be distinguished 

 during the month, but climatic factors will often bring about 

 a totally different story for any given season. As a general 

 rule the following species arrive between May 2nd and May 

 7th, and a " wave" usually occurs in this period bringing the 

 majority of them with it. Those marked with an asterisk (*) 

 occasionally arrive the last days of April. The balance are 

 casual in April, but in the remarkable spring of 1914 the 

 majority arrived on April 29th and 30th: 



