WINTER BOOSTING COLONIES OF CROWS. 339 



by all the rest. Never before had I realised the almost infinite 

 possibility of the Crow's variable "caw" in the production of 

 discords. This great noise, which the poetic soul of Audubon 

 conceived to be "thanksgiving" and "consultation," was kept up 

 for twenty minutes before any movement was discernible. Then 

 about a dozen Crows started off for the day's work, followed by 

 more and more, until they were going from the roost much as 

 they return to it in the evening, in three or more large streams. 

 The Crows, however, were then much more scattered in the 

 order of flying than in the evening streams. After they had been 

 leaving thus for about twenty minutes, the streams constantly 

 growing larger, a common impulse seemed to move a large 

 number of Crows, and they did not wait to "fall in" as indi- 

 viduals, but suddenly joined the stream as a large flock. The 

 streams were thus swollen in bulk quite regularly about every 

 five minutes until the colony had dispersed. In an hour's time, 

 or just at sunrise, the whole body, with the exception of twenty 

 or thirty, evidently too weak to go far off, had left the roost. All 

 this time the din of the general body does not seem to diminish, 

 those left behind apparently doing double duty in the " thanks- 

 giving," while those going away, as far as one can hear, do not 

 fail to keep up their cawing. In this respect tliey differ from 

 the evening streams, which in the main come in with but little if 

 any noise. In seeing this morning dispersion I think one is 

 impressed, even more than in the evening, with the vast number 

 of Crows constituting the colony. 



In the daytime the individuals are scattered all over the 

 surrounding country, seeking food in the fields, along the shores 

 of bay, river, and creek, one and two together, and then in rather 

 large flocks at the glue factories and stock-yards if there chance 

 to be such rich grounds in the neighbourhood. They disperse to 

 a radius of from one to about forty miles over the fields and 

 along the water-courses. I have seen them scattered all the way 

 from Baltimore to Philadelphia on the one side and to Washington 

 on the other. Of course these Crows were members of two or 

 more colonies. 



Mr. Rhodes says that " during winter a radial sweep of one 

 hundred miles, described from the city of Philadelphia and 

 touching the cities of New York, Harrisburg, and Baltimore, will 

 include in the daytime, in its western semicircle, fully two -thirds 



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