14 University of California Publications in Zoology [Vol. 12 



In testing the above characters upon the large series of geese avail- 

 able in the present study many proved so extremely variable as to be 

 of no practical value, while others are based entirely upon miscon- 

 ceptions. 



Careful examination of the series of geese at hand justifies the fol- 

 lowing diagnoses as more nearly expressing the differences existing 

 between the four subspecies. 



Branta canadensis canadensis 



Size large. 



Tarsus usually shorter than middle toe and claw. 



Color of under surface of body pale gray; much lighter shade than back. 



Black of neck abruptly defined against gray of breast. 



Gray of lower surface fading gradually into white of crissum. 



White cheek patches usually confluent across throat; occasionally a few 

 black spots along median line of throat; or slight encroachment of 

 black indicating the beginnings of the black isthmus. 



White collar at base of black neck usually absent; occasionally faintly 

 indicated. 



Number of rectriees 14 to 20 (usually 18). 



Measurements in millimeters. Wing, 418-527 (500.6); tail, 134-174 

 Minimum, maximum, and (156.8) ; culmen, 47-58 (52.4) ; tarsus, 

 average of ten adult males. 76-98 (92.3); middle toe and claw, 

 77-106 (97.3). 

 Branta canadensis occidentalis 

 Size large. 



Tarsus as long as, or slightly longer than, middle toe and claw. 

 Color of under surface of body dark; broccoli brown, about same shade 



as back. 

 Black of neck abruptly defined against brown of breast. 

 Brown of abdomen abruptly defined against white crissum. 

 White cheek patches usually confluent across throat; occasionally a few 

 black spots along median line of throat, or slight encroachments 

 of black indicating the beginnings of the black isthmus. 

 White collar at base of blaek neck usually absent; occasionally faintly 



indicated. 

 Number of rectriees 14 to 18 (usually 18). 



Measurements in millimeters. Wing, 433-495 (465.7); tail, 134-154 

 Minimum, maximum, and (142.7); culmen, 48-51 (48.7); tarsus, 

 average of four adult males. 86-99 (92.2); middle toe and claw, 

 83-95 (87.2). 

 Branta canadensis hutchinsi 

 Size medium. 



Tarsus about the same length as middle toe and claw. 

 Color of under surface variable; pale gray to dark brown. 

 Pattern of head and neck markings variable. Black dividing line on 

 white throat may or may not be present. White collar at base of 

 neck may or may not be present. 

 Number of rectriees 16 to 18 (usually 16). 



