40 The Ornithology of Chester County 



October lo. 



42. Nycticorax nyticorax nycticorax Black-crown- 

 ed Night Heron, "crane," "Indian hen," "mudhen," 

 "mudpoke," "night heron," "qua-bird," "squawk." 

 Common summer resident, extremely local as a 

 breeder. Barnard considered it rare in his neigh- 

 borhood, and Montgomery never met with it in the 

 vicinity of West Chester. I have found it rather 

 common along the Octoraro below Atglen, and 

 Harry Wilson reports it probably nesting along 

 Buck run in East Fallowfield Twp., but I believe 

 that these birds are all from the Lancaster county 

 colonies. There is a large herony in the eastern 

 part of the Chester valley, in Tredyffrin Twp. 

 (Burns, Bird-Lore, xix, 197). Nidification begins 

 soon after arrival, average date for complete set, 

 May lo. Thomas notes its arrival at Kennett 

 Square, Apr. 12 (1908) — Apr. 22 (1915), and it 

 doubtless averages several days earlier at its breed- 

 ing grounds than I am able to offer for Berwyn 

 vicinity : 



Arrival — Apr. 15 (191 7) — Apr. 30 (1906) ; ave, 

 7 yrs. Apr. 20. ' 



Departure — Oct. 6 (1911) — Nov. 6 (1893); 

 ave. 3 yrs. Oct. 23. 



43. Nycticorax violacens Yellow-crowned Night 

 Heron. Rare summer resident. On May 14, 1915, 

 I found it present and evidently nesting in the 

 local colony of N.n.nycticorax. An individual, prob- 

 ably not always the same one; was observed circling 

 just above the tree tops on three occasions, and I had 

 a view of it through the glass while it perched close 



