30 The Ornithology of Chester County 



4. Gavia immer fyoon, "big diver,'' ''great north- 

 ern diver." Not common transient visitant, though 

 it appears on all our county lists. Migration dates : 

 Apr. 26 (i9i5)-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, vvrhen 

 it vi^as 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, 191 1; 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 II, 1890 (Stone, 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 delawarensis Ring-billed Gull. During 

 a severe storm from the west. Mar. 28, 191 1, a crip- 

 pled straggler was captured on Greystone farm. East 



