NATURAL SCIENCES OP PHILADELPHIA. 33 



March. Some flocks that I witnessed must have contained 

 thousands of birds. These were not the species just named, but 

 whether hudsonicus or horeaUs was not ascertained. 



Recurvirostra americana. 



I scarcely think that this is a regular, and it certainly is not, 

 according to ni}^ observations, a common migrant here. The only 

 time I identified it with certainty, was on the 12th of September, 

 when a flock of six was seen. 



Ardea herodias. 



A resident species, common on the marshes at all seasons. 

 This and the Bittern are the only species of the family that I 

 observed in winter. I do not know that it breeds in the imme- 

 diate vicinity, but such is probably the case. 



Herodias egretta. 



Onl}^ observed late in summer, and through autumn, when 

 moderate!}^ common, and generally seen in small flocks. 



Garzctta candidissima. 



Apparentl}^ a summer resident, though not observed breeding. 

 I first saw it early in Ma}^, when it appeared to be migrating, but 

 individuals were obtained at A'arious times during the summer. 

 The}^ were oftenest in flocks of considerable size. Old bii'ds killed 

 in July still had lengthened plumes on the head and breast, but 

 the former were not recurved, and the dorsal ones were wanting. 

 Except in these respects, the birds of the year were like the adults. 

 They remain until October at least, and probably later. 



Butorides virescens. 



Summer resident, and very abundant, arriving late in March 

 and early in April, and remaining until October. They breed in 

 colonies with the jackdaws, placing the nests in the thick shrub- 

 bery that covers part of this end of the island. The nests are 

 rather large and frail platforms of loosely interlaced twigs, built 

 on dense beds of small branches, or saddled in a crotch, or swung 

 like hammocks upon a mass of climbing vines. The birds begin 

 to lay the second or third week in April, but some do not fill the 

 nest until after the first of May. The complement is usually five 

 or six; but I ha^e found only four, and in one instance seven — 

 the latter number probably being the maximum. The old birds 



1871.] 



