118 University of California Publications in Zoology [Vol.12 



Twelve specimens of this heron were secured, two (nos. 12625, 



12626) from the California side near Riverside Mountain, one (no. 



12627) from the Arizona side at Ehrenberg, and nine (nos. 12628- 

 12636) from the California side about ten miles below Ehrenberg. 

 In the accompanying table of measurements of the fourteen appar- 

 ently mature specimens a wide variation will be noted. While the 

 largest individuals of the series are males, some females are larger 

 than some males. I find nothing to indicate that size increases with 

 age, though this might fairly be expected. The average of the serie.s 

 accords closely with the measurements given by Court (1908. p. 292) 

 for Ardea lierodias tregamai (except as resulting from obviously dif- 

 ferent methods of measuring. a.s with middle toe). 



The status of the great blue herons residing in California west of 

 the Sierran divide has been recently settled by Oberholser (1912, p. 

 550). As compared with these all of the Colorado River skins are 

 markedly pale throughout, with reduction in extent of dark areas. 

 Bills straw yellow, darkening on eulmen, not "black." as stated by 

 Court (1908, p. 291). 



The weights of two freshly killed males were 5i4 and 5% pounds, 

 of two females 5 pounds each. 



MEASUREMENTS IN MILLIMETERS OF ABDEA HJiEODIAS TBEGANZAI 

 FROM THE LOWER COLORADO RIVER AND VICINITY 



' The plumage of this specimen is not in full breeding condition, and the 

 bird may not have been full grown, in respect to flight feathers especially. 

 = Pelican Island, Salton Sea, Calif., April 20, 1908. 

 ^ Silsbee, Imperial Co., Calif., April 4, 1909. 



