322 Wood, Autumn Warbler Migration. [julv 



AUTUMN WARBLER MIGRATION. 



BY J. CLAIRE WOOD. 



In 'The Auk,' Vol. XXIII, No. 1, January, 1906, I gave an 

 account of the Warblers noted here in the autumn of 1905. That 

 season I devoted my entire spare time to them from August 20 but 

 this autumn I did not start until September 3; consequently, the 

 following list is inaccurate as to first arrivals but I doubt if anything 

 escaped notice from September 3 to the end of the season. A 

 Mourning (Geothlypis philadelphia) and several Nashville Warblers 

 were seen in 1904 but were absent in 1905, while the Tennessee 

 was absent in the former season and common in the latter. This 

 irregularity in warbler migration was interesting, and I wished to 

 learn what percentage of species were subject to it and also to 

 establish a better knowledge of the relative abundance and time of 

 departure by a comparison with the present season of 1906. To get 

 the most uniform results I hunted over the same territory, with the 

 exception of one or two days, and the comparison was satisfactory 

 until displaced by an abnormal change in temperature. During 

 the night of October 9 the mercury dropped to 33°, and we had a 

 genuine heavy snow storm on the 10th, but the snow melted as it 

 fell. Toward evening the mercury began to drop and reached 25° 

 at 3 A. M. on the 11th where it remained for three hours. This 

 killed all plant life, susceptible to frost, and its blighting influence 

 was noticeable throughout the woods on the 14th; even the live 

 oak leaves were affected, while the beeches w r ere a mass of yellow 

 and no longer yielded a food supply to the warblers. With the 

 exception of Black-throated Blue and Myrtle, all the species seen 

 that day were hurrying south under pressure of unnatural excite- 

 ment, and had probably undergone considerable hardship, as the 

 ground was covered with half a foot of snow sixty miles north of 

 here and about three inches at half that distance. 



The woods, where I hunted, had been greatly reduced in size 

 since 1905, and I was able to note the course of arrivals in many 

 cases and departure in nearly all. The length of the River Range 

 is about thirty miles and its general course approximately S. 45° E. 

 This woods is situated on the south side and is the last piece of 



