40 The Ornithology of Chester County 
October 10. 
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 ITwp., 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 10. ‘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 (1917)—Apr. 30 (1906) ; ave. 
7 vxs.\ 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 | had 
a view of it through the glass while it perched close 
