46 Bulletin No. 15. 



but none ventured into the trees at first. They came from the south-east 

 in companies of from five to ten individuals, avoided the trees of the 

 roost and settled in the grove on the west side of the campus. At 7:00 

 more than fifty cowbirds from these trees came dashing into the roost 

 and disappeared at once. A little later a smaller company dashed in. 

 From this time on the cowbirds flew directly to the roost without mo- 

 lestation from the grackles ; previously the grackles had resisted attempts 

 to share the roost with them. None of the cowbirds were singing, and 

 but few uttered the whistling note. There were about 100 cowbirds, but 

 no robins. 



The contrast between the actions of the birds early in the season and 

 relatively late will be made evident by the record of the departure and 

 arrival of the grackle host on September 7. The sky was clear, the air 

 chilly but still, temperature 50 in the morning. Station : 300 feet west 

 of the roost, commanding a view of the north, west and south-west sides. 



Arrived at the roost at 3:30 a. m. No birds stirring. 



4:00. The first sleepy note was heard. 



4:15. Several awakened and sang. 



4:30. Many were singing and shifting about in the trees. 



4:40. Very noisy, and much shifting about. Cowbirds began to leave. 

 By 4:50, 300 counted leaving, 



4:50. Several hundred grackles came to the roost from the neighbor- 

 ing trees where they had passed the night. 



4:55. Grackles coming from all directions and settling in the roost 

 with much noise and scolding ; the most sink out of sight. 



5:04. Several come from the north-west, the most stop in the roost, 

 but as the rear guard passes on southward those in the roost rise and fol- 

 low in one continuous stream which flows up out of the trees where 

 few birds were seen before, over the still slumbering village and away 

 into the south-west, leaving an oppressive stillness where a moment ago 

 the air was filled with their voices. The birds did not rise from the trees 

 in one mass as we have so often seen them do, but in consecutive order 

 from the south to the north edge of the group of trees, as though by pre- 

 vious arrangement, giving the impression that the foliage was melting 

 away into that black stream. The appearance of the departing birds 

 created a strong impulse to be up and follow them. I did follow them 

 well out into the country, but soon found myself hopelessly beaten in the 

 race. As long as it could be seen, the flock remained intact, and did 

 not stop to rest. The flight was near the ground, and followed the con- 

 tour of the country closely, rising only to clear farm buildings and woods, 



