140 Tyler, Call-notes of Migrating Birds. [April 



flights. As I have never heard the "tcheck" note during the night 

 from migrating birds, I presume that Myrtle Warblers make use 

 mainly, if not solely, of the sibilant note as a migration call, once 

 the flight is well under way. 



"On the afternoon of the 12th (the next day) the behavior of the 

 Myrtle Warblers at twilight was very different. Mr. Faxon and 

 I had spent the afternoon at Coffin's Beach, Gloucester, and toward 

 dusk we crossed a broad area of level land, just back of the beach, 

 grown up thickly with bayberry bushes, with a sprinkling of blue- 

 berry and a few pitch pine trees. This growth made a dense tangle 

 of branches not rising more than six feet from the ground (except 

 in th^ case of the pine trees) and over the whole expanse one spot 

 was pretty much like another. Throughout this space. Myrtle 

 Warblers were hopping about restlessly, chipping excitedly, and 

 taking short flights. As it grew darker, the birds quieted; they 

 remained longer in a bush when they found one to their liking and 

 hopped among the branches, evidently searching for a comfortable 

 and safe perch to sleep on. They allowed us to step very near 

 them before they flitted away to a neighboring shrub. The birds 

 did not appear to gather into flocks or companies; two or three, to 

 be sure, might be examining the same bush, but everywhere over 

 the area of forty acres or so, as far as our eyes could see, scattered 

 birds were settling for the night; evidently there was to be no 

 Myrtle Warbler migration. We noted these birds between 5 and 

 5.15 P.M. At this time there were no birds flying into the field 

 as there would have been if the Warblers were assembling from a 

 larger area." 



It is not always possible to estimate the magnitude of a flight 

 by the number of bird-notes heard during the night. Extensive 

 migratory movements often occur in spring during a night when 

 few, if any, notes are heard, and conversely, one is often surprised 

 in the autumn to find the country practically barren of bird-life 

 after a night during which birds' "chips" have been heard in great 

 numbers. 



This latter condition may be easily explained, I think. During 

 the night the birds are passing in hundreds or thousands, but at 

 dawn each bird or flock settles near wherever it happens to be. 

 Hence in any one locality, once the stream is stopped, there will be 



