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WBSSeCRjy OKOIGBOLOGY' 
Volume XVIII 
November-December, 1916 
Number 6 
SOME RESULTS OF A WINTER’S OBSERVATIONS IN ARIZONA 
By A. BRAZIER HOWELL 
T HE SECTION of country contiguous to old Fort Lowell, a few miles east 
of Tucson, Arizona, is one of peculiar interest to ornithologists, for here 
much pioneer work was accomplished by certain of the “old guard,” such 
as Major Ben dire, and, at a later date, by several of our contemporaries. But 
little has been done in this region during the winter months, however, and partly 
for this reason I spent the time from December 7, 1915, until March 25, follow- 
ing, some twelve miles east of Tucson, encamped at an altitude of 2500 feet on 
Rillito Creek, which flows (occasionally) down an arid valley in a pocket between 
the Rincon and Santa Catalina mountains. In view of the previous extensive 
collecting carried on hereabout it is hardly worth while to give an annotated list 
of the birds encountered by myself, but a few notes concerning certain species 
may prove of interest. 
Due to the situation of our camp, and to the fact that I was unable to absent 
myself over night, my work was confined to the Lower Sonoran zone. In spite 
of the fact that I walked as far as seven miles up the canyons from their mouths, 
at no time was I above the sahuaro association. The height of this zone here, at 
least 3700 feet, on the sides of the canyons, and higher on the ridges, is caused 
both by the southern exposure and by the high base level. It was only at the 
highest point reached that I caiTght glimpses of such birds as jays and spotted 
towhees. 
Several forms which are not at all uncommon about Tucson seemed to be 
entirely lacking from our vicinity, notwithstanding the fact that the former 
place can be only a few feet, possibly seventy-five, lower than the latter, and 
very similar in character. Yellow-headed Blackbirds ( Xanthoceplialus xantho- 
cephalus) were seen about town, but not where we were. Similarly with White- 
necked Ravens ( Corvus cryptoleucus ) , although I did note several large flocks 
wheeling in seemingly aimless circles far above camp, for hours at a time, which 
evolutions I judged to be some form of early courtship. In the nearby mesquite 
