DELAWARE VALLEY ORNITHOLOGICAL CLUB. 13 



nesting duties. Although there may be a small nesting colony 

 in the roost itself, practically all the birds nest in various ever- 

 green clumps about the neighborhood. For a brief period, four 

 weeks according to Mr. Lynds Jones, ^ the Grackles appear to 

 stay about the nesting colony trees, although Mr. Peck's ob- 

 servations showed that even at this time from two to three thou- 

 sand returned to the Overbrook roost every night, and Mr. 

 Emlen states in regard to the Germantown roost that "all 

 through the nesting season quite a large number of birds came 

 back to spend the night." It seems hardly probable that a 

 large number can be referred to unmated birds. Certainly as 

 soon as the females commence to incubate, the old males start 

 to make their nightly trips to the roost, leaving the females to 

 guard the nests. As the young mature they Join the old males 

 in the sunset flight until by the middle of June, when nesting 

 duties are over, they commence to appear in flocks of some 

 size. (Mr. Pennock noted 250 June 12th. ) Up to this time the 

 Grackles come into the roost from all directions, apparently 

 from the scattered nesting colonies, but as soon as the nests are 

 completely abandoned and the birds have taken to their feed- 

 ing grounds, definite lines of flight are established to the roost 

 and these lines are followed by detached companies of birds. 

 The establishment of flight-lines occurs about the last week in 

 June. 



In regard to one particular flight-line Mr. Stone writes: "For 

 some years past I have noticed during late June and July a 

 regular evening flight of Purple Grackles passing over my home 

 near 51st St. and Hazel Ave., West Philadelphia, in a north- 

 easterly direction toward Kirkbride's Insane Asylum at 46th 

 and Market Streets. My idea of this evening flight was that it 

 represented the old and young from the asylum grounds, return- 

 ing from their day's feeding along the Schuylkill or Delaware, 

 to their nesting-place to roost. This year I paid closer attention 

 to the flight than during any previous season and came to the 

 conclusion that the flight of mid-July w^as altogether too large 

 to be referred wholly to the birds breeding about the asylum." 



' Bulletin 415 Wilson Ornithological chapter of the Agassis Assoc. 



