88 The Ornithology of Chester County 
Berwyn: 
Arrival—Apr. 21 (1893)—May 12 (1914) ; ave. 
25 yrs. May 4. 
Common—Apr. 29 (1893)—May 17 (1902- 
1917); ave. 23 yrs. May 10. 
Bulk departure—Aug. 31 (1903)—Oct. 7 (1895- 
1897) ; ave. 13 yrs. Sept. 21. 
Last seen—Sept. 18 (1891-1901)—Oct. 26 
(1900) ; ave. 20 yrs. Oct. 6. 
179. Vireosylva philadelphica Philadelphia Vireo. 
Rare transient. Josiah Hoopes captured specimens 
at West Chester, Sept. 30 and Oct. 6, 1891 (Stone, 
Bds. E. Pa. and N. J., 126); and I shot an adult 
female (No. 685, coll. F. L. B.) Sept. 19, 1898, at 
Berwyn (Wils. Bull., 24, 7); the above appear to 
be the only records for the county. 
180. Vireosylva gilva gilva Warbling Vireo. Tol- 
erable common summer resident. W. L. Baily found 
newly made nest at Paoli, May 18, 1891. 
Berwyn: 
Arrival—Apr. 30 #(1906-1908)—-May 12 
(1914); ave. 14 yrs. May 7. 
Common—May 8 (1916)—May 15 (1915); 
ave 3 yrs. May 11. 
Departure—Sept. 4 (1913)—Oct. 7 (1910); 
ave. 8 yrs. Sept. 19. 
181. Lanivireo flavifrons Yellow-throated Vireo. 
Not common summer resident. W. S. Hall took a 
set of eggs, Willistown, July 2, 1884; and the 
writer found two nests: Valley Forge, June 11, 
1885, and Berwyn, June 18, 1899. 
Berwyn: 
