136 Tyler, Call-notes of Migrating Birds. LApril 



Henry H. Kopman (Auk, Vol. XXI, 1904, pp. 45, 46) heard the 

 Veery utter by day a note which had puzzled him for years as he 

 heard it from nocturnal migrants. It is evident, however, that he 

 may not have differentiated this note from the calls of other 

 Thrushes, for, although he had heard "countless hundreds" of the 

 calls, he had noted less than a score of Veeries in ten years of ob- 

 servation, while he had met the Gray-cheeked and Olive-backed 

 Thrush "in astonishing numbers" at the very season when he 

 heard the nocturnal whistles. 



The Veery call is most common in late August; my earliest and 

 latest dates are August 12 and September 5. On some nights the 

 calls come so frequently that, at times, there are but a few seconds 

 between them; on other nights there is scarcely one to be heard,— 

 a point of difference from the comparative regularity of the "x" 

 note. 



After the Veery call ceases for the season, there is generally an 

 interval of about a week before a second whistle is heard. Al- 

 though of the same general character as the Veery call, this late 

 September whistle is pitched higher. It is of somewhat less dura- 

 tion, and is inflected downward very little, if at all, and lacks the 

 terminal roll or roughness characteristic of the Veery call. My 

 notes for the past four years indicate the migration period of this 

 later bird to be between September 8 (an extremely early date) and 

 September 27. I may say that these two "Thrush whistles" and 

 the note next to be considered are so nearly identical that, for two 

 or three years, I did not distinguish between them clearly, hence, 

 I cannot use the dates contained in my earlier records. The late 

 September call is a very frequent note on nights of heavy migra- 

 tions, — so frequent as to indicate that it is uttered by a very 

 common migrant. For this reason I believe that it is the call-note 

 of the Olive-backed Thrush, in spite of the fact that of all diurnal 

 bird-notes, it most resembles the whistled "hear" of Hylocichla a. 

 bickncUi. An article in ' The Oologist ' (Vol. XXXI, 1914, pp. 162- 

 166), by Paul G. Howes deals with the migration call of Swainson's 

 Thrush. Mr. Howes' studies were made during the autumn of 

 1912 at Stamford, Conn. He describes the migration period as 

 materially longer than my records indicate, his last bird passing 

 southward on October 17. Mr. Howes was fortunate in being 



