Jam., 1922 SOME BIRDS OF ROOSEVELT LAKE, ARIZONA Os 
treme ends of the lake and at two or three places along the northern side, the 
shores are steep and in many places almost precipitous. 
The general topography in the vicinity of Roosevelt Lake is rough and 
broken. On the west side of the northern arm of the lake, where most of the 
field work was conducted, the soil covering is slight, the basal structure being 
largely a reddish limestone, inter-mixed with conglomerate and granite. Bum- 
blebee Canyon drains the region of Mazatzal Range adjacent and just north 
of Four Peaks. This canyon is terraced much of its length through a gravel 
soil washed from the hills above. Underground water oozes to the surface in 
many places to form Bumblebee Creek, the actual stream being less than a 
mile long in dry weather. It was near the mouth of this creek that headquar- 
ters were made May 19 to 24. 
The entire region adjacent to Roosevelt Lake lies in the Lower Sonoran 
Zone, which is here characterized by the growth of such plants as Covillea glut- 
Fig. 12. Map or ROOSEVELT LAKE, ARIZONA. CIRCLES INDICATE APPROXIMATE LO- 
CATIONS OF BREEDING COLONIES OF CORMORANTS AND HERONS. 
inosa, Prosopis glandulosa, Acacia greggi, Fouquieria splendens, Hymenociea 
monogyra, Gutierrezia sp., Carnegia giganteum, Dasylirion wheeleri, Yucca radi- 
osa, and Chilopsis linearis. The aspect is distinctly that of desert mountains. 
Phalacrocorax auritus albociliatus Ridgway. Farallon Cormorant. This species 
was found breeding in dead cottonwoods, the tops of which protruded above water fifteen 
to forty feet deep. The nests were usually about fifteen to twenty feet above the water, 
never under twelve feet above the surface. The water, however, had receded about six feet 
during the nesting season. All the nests examined contained young from a week or ten 
days old, to birds well feathered and nearly able to leave the nest (the greatest part of 
the young were this age), and to a few able to fly and swim. All told, there were about 
130 pairs of cormorants breeding on the lake, about 90 pairs at the Salt River end, and 
about 40 pairs at the Tonto Creek end. Swarth (loc. cit., p. 52) estimated the number 
at the mouth of the Tonto as 40 or 50 birds. 
