3O The Ornithology of Chester County 



4. Gavia imrner fxjon, "big diver," "great north- 

 ern diver." Not common transient visitant, though 

 it appears on all our county lists. Migration dates : 

 Apr. 26 (191 5) -May 30 (1909) and again Nov. 

 14 (1908) -Nov. 25 (1909). A flock appeared in 

 the Chester valley on Nov. 14, 1908, during a N. 



E. snowstorm, and a pair secured from a small dam 

 on the Chesterbrook farm (Nos. 934 and 935, coll. 



F. L. B.) ; another female lingered on a pond a 

 mile further up the Valley creek until Dec. 10, when 

 it was found dead and in an emaciated condition 

 (Burns, Wils. Bull., 65, 215, and 66, 18). Under 

 similiar circumstances another catastrophe occurred 

 Nov. 25, 1909; two birds were shot at Paoli, two 

 at Lenape and one seen on a pond near Westtown 

 (Redfield, Ibid., 70, 56). 



5. Gavia stellata Red- throated Loon. Straggler. 

 A female (No. 988, coll. F. L. B.) shot on Trotter's 

 dam, near Berwyn, Nov. 15, 1911; is the sole 

 county record (Burns, Auk, xxxii, 1915, 225). 



6. Larus argentatus Herring Gull, "gull," "sea- 

 bird." Rare transient and winter visitant. The 

 following are all the records known to me : Central 

 Chester Co., five noticed flying high overhead, even- 

 ing of May n, 1890 (Stcne, Birds E. Pa. and N. 

 J., 43) ; Berwyn, flock of sixteen going west at noon, 

 Feb. 19, 1902, and Valley Forge, a single one on the 

 Schuylkill, Jan. 6, 1903 (Burns MS.) ; and Ber- 

 wyn, two on Apr. I, 1908 (Redfield, Cass. xii, 53). 



7. Larus delawiircnsis Ring-billed Gull. During 

 a severe storm from the west, Mar. 28, 1911, a crip- 

 pled straggler was captured on Greystone farm, East 



