EASTERN CROW 227 



but banding operations conducted in Oklahoma by Kalmbach and Aldous 

 (1940) prove that many of the crows wintering in that State migrate 

 to the Prairie Provinces of Alberta, Saskatchewan, and Manitoba, a 

 flight of more than a thousand miles. One crow shot at Meadow Lake, 

 Saskatchewan, at latitude 54° N. had traveled 1,480 miles and another at 

 Camrose, Alberta, 1,435 miles from their winter home in Oklahoma. 

 Out of 714 crows banded, 143 recoveries were obtained. Of 65 crows 

 recovered during the nesting season, 49 were from the Prairie Provinces. 

 It is obvious that many of the returns recorded in the States north of 

 Oklahoma were on their way to or from the Canadian breeding grounds. 

 The results obtained by Kalmbach and Aldous not only give us definite 

 information concerning the extent of crow migration but are important 

 in their relation to the value of the extensive control measures under- 

 taken in Oklahoma. 



Crows have been used for important experimental work concerned 

 with different phases of migration. William Rowan, proceeding on the 

 hypothesis that the migrating stimulus is a physiological one originating 

 in the gonads or sexual organs, experimented on various birds, but 

 chiefly the crow. The crows were confined in outdoor aviaries at Ed- 

 monton, Alberta, and exposed to temperatures as low as 44° F. belov/ 

 zero, but from the first of November until early January they were sub- 

 jected to an ever-increasing amount of light, supplied by electric bulbs. 

 In this way they were artificially subjected to light conditions that ap- 

 proximated those of spring. At the close of this period it was found 

 that the gonads had actually attained the maximum development nor- 

 mally associated with the spring season. Control crows not subjected 

 to the light treatment showed no development of the gonads. The 

 birds, both the light-treated individuals and the controls, were marked, 

 banded, and then liberated. By means of radio and other publicity, the 

 cooperation of hunters was solicited for the return of the bands. While 

 bands from eight of the experimental crows were returned from the 

 north and northwest (two of them from a point 100 miles northwest of 

 the point of liberation), an equal number were recovered from the south 

 and southeast, thus to some extent nullifying the experiment. This 

 work does indicate that the stimulus that initiates migration is a 

 physiological one, and it is assumed to be a hormone produced by the 

 interstitial tissue of the reproductive organs. 



Courtship. — Edward J- Reimann in correspondence writes of the 

 early courtship of crows he observed in the vicinity of Philadelphia. 

 Pa. On March 8, 1940, he saw crows paired at most of the nesting 

 localities along the Pennypack Creek. In some of these places tvvo or 

 three birds and at times four or five, vv'hat he supposed to be males, were 



