116 University of California Publications in Zoology [Vol.12 



Erismatura jamaicensis (Gmelin) 

 Ruddy Duck 

 Four noted on a sand bar in the river four miles above the Laguna 

 Dam. April 23; one secured: immature male. no. 12624. 



Chen hyperboreus hyperboreus (Pallas) 

 Lesser Snow Goose 

 February 16 two small flocks were seen at Needles flying south; 

 February 23 a flock was met with on a mud bar on the California 

 side between Needles and Mellen. 



Plegadis guarauna (Linnaeus) 

 White-faced Glossy Ibis 

 A dozen seen May 5 flying down the river along the Arizona shore 

 four miles above Yuma. 



Mycteria americana Linnaeus 

 Wood Ibis 

 A flock of twelve individuals seen April 21 flying up the river, at 

 a point about four miles above the Laguna Dam. Said by residents 

 of the region to occur abundantly along the river at the present time, 

 just as recorded in the '60 's by Coues (1866, p. 96) and Cooper (1869, 

 p. 481). 



Ardea herodias treganzai Court 

 Pallid Blue Heron 



Abundant resident along the whole course of the river as far as 

 explored. Nesting colonies were observed in trees at many points 

 through the large valleys; and one group of nests was noted on a 

 pinnacle of rock in the narrow canon just below The Needles. Ordin- 

 arily nests were placed in the tips of the largest cotton woods in the 

 neighborhood. Special predilection was evinced for dead trees stand- 

 ing close to the river. This would seem to be because of the clear 

 fly- way afforded to and from the nests; and because of the more 

 extensive outlook possible. But there were in this region drawbacks 

 to these advantages. 



In a number of places the river was rapidly undercutting the 

 outside curve of its bank, on which stood occupied nest trees. Though 



