96 The Ornithology of Chester County 
Ladd, recorded the nesting of this bird on the South 
Valley hills not far from Frazer, May 27, 1900 
(Abst. Proc. Del. Orn. Club, iv, 4), the set of four 
eggs are now in the Norris collection; Pennock ob- 
served a single bird in deciduous woods two miles 
beyond the serpentine barrens in the southern part 
of the county and not more than 250 feet above sea 
level, on June 16, 1911 (Auk, xxix, 247); and I 
found a nest with two young and one infertile egg 
at Berwyn, July 10, 1914 (Wils. Bull., 90, 288). 
Berwyn: 
Arrival—Apr. 30 (1916)—May 16 (1917) ; ave. 
10 yrs. May 8. 
Common—May 8 (1909)—May 23 (1915-16) ; 
ave. 8 yrs. May 14. 
Departure—Sept. 28 (1889)—Oct. 8 (1891) ; 
ave. 5 yrs. Oct. 3. 
201. Dendroica castanea Bay-breasted Warbler. 
Not common transient. 
Berwyn: 
Spring arrival—May 8 (1909)—May 18 
(1917); ave. 4 yrs. May 13. 
Spring departure—May 19 (1905)—May 30 
(1917); ave. 5 yrs. May 23. 
Fall departure—Sept. 16 (1891)—Oct. 5 
(1895) ; ave. 3 yrs. Sept. 26. 
202. Dendroica striata Black-poll Warbler. Com- 
mon transient. 
Berwyn: 
Spring arrivam—May 12 (1914)—May 16 
(1896) ; ave. 4 yrs. May 16. 
Spring departure—May 16 (1904)—June 1 
