CROW ROOSTS IN MARYLAND. 17 



observed it literally 'brings down the house,' and when one imagines 

 the simultaneous shout of 20 acres of Crows, one may not wonder 

 that 'the house' is fully able to bring down the Crows. The few Crows 

 resume their perches and comparative quiet is restored. 



"Numerous attempts are thus made with a like result until nearly 

 sunrise, when detachments of 500 to 1,000 successively take wing amid 

 the wildest enthusiasm. These circle and wheel about in headlong- 

 swoops and elegant curves above the forest, and, each having taken his 

 bearings, moves off in one of the many lines of flight that, eastward, 

 westward, to north and south, extend from the common center as the 

 spokes of a wheel. 



" Ere the sun looks out upon the scene a silence almost oppressive 

 broods over field and woodland, and to one who so recently beheld 

 this departure, a scattered remnant of the mighty host only serves to 

 heighten the feeling of contrasted desolation." 



In 1888 Mr. C. L. Edwards, 1 then of the Johns Hopkins University, 

 published the results of careful observations made on a large roost near 

 the city of Baltimore. Perhaps the most valuable part of this paper 

 is the attempt to estimate the number of Crows using this roost. 

 Much difference of opinion has existed among observers as to the num- 

 bers resorting to any particular roost, the estimates for the same colony 

 ranging all the way from 5,000 to several millions. It has been gener- 

 ally assumed that the numbers were much overestimated, since most 

 attempts to number the birds have been scarcely more than guesses. 

 Mr. Edwards 7 results may be accepted with some degree of confidence. 

 He says: 



"Seven miles southwest from Baltimore, a half mile southeast of 

 Arbutus station on the Baltimore and Potomac Railway, is a tract of 

 land of about a half mile square on which are several patches of- 

 woods which furnish the roosting ground for a winter colony of Crows. 

 It seems from the testimony of the owners of this land that the crows 

 have roosted there for about twelve years, having previously occupied 

 a piece of woods a half mile or more to the westward, which they aban- 

 doned when housebuilding and woodcutting by the inhabitants made 

 it undesirable. *'*_.* 



"A determination of the exact number of Crows here collected is not 

 possible, but even the most sober observers place it among the hun- 

 dreds of thousands. As a basis for an approximate calculation, I have 

 made the following observations at the roost. With the aid of two 

 friends, 15 different square rods, taken here and there at random, were 

 paced off, and the number of trees thereon capable of furnishing roost- 

 ing tops counted. An average gave us 9| trees per square rod. At 

 any one roosting the Crows occupy about 10 acres (160 by 9f by 10), 

 or 15,360 trees. If on each tree 15 Crows roosted — and that, if any- 



1 Am. Journ. Psychology, I, May, 1888, No. 3, pp. 443, 453-454. 

 3086— No. 6 2 



