Sept., x9oo I THE CONDOR xot munk 'during his life undergoes a far greater rate of mortality than the birds do from various sources, so that the large annual increase is almost lost by the advent of the following season and nature's balance is thus maintained. that of the birds and were it not checked yearly they would soon overrun their range to the exclusion of all the more susceptible forms of life in it and nature's natural adjustment of all varie- ties of life would be lost; hut the chip- Nesting of the Itivoli liummingbird in Southern Arizona BY O. ?. 1fO.'ARD, FT. In'ACHUCA, ARIZ. [Read I)efi?re the Southertl Division of the Cooper Orn. c'lub. Jnly 20. ?9ool URING the spring of ?899, while lint was somewhat encouraged wheu camped near the summit of the one morning early in Jtfiy a female Hu?chuca Mountains, Ariz., I Rivoli Hmnmer made her appearance spent considerable time watching the at our cam 1) and hegan pulling from a few Rivoli Hummingbirds (lu?cm's pine stump some cotton which I had ./Mgens) which I chanted to see, io hope placed there, thinking it nfight he the of finding a nest rr two. The 1)irds means of tracing some bird to its nest. P I.ATE I. were generally lu;vering over flc, wers, evidently feeding, and would :oon d!s- appear in the distance, possibly to the maples in the cam:ns helow where they usually nest. I had about given u 1) finding any nests, as the svas{ n wr.s well advanced, I'ltnla b_r ('. H: 1to?c,atd NEST .AND I?(;(;S )F RIVOLI Ht'?.X'?iX(;mRt) (/u.?,'cncs./}//.'cns) After Mrs. Rivoli had helped herself to the dainty morsel she flew in a direct line to the linttom t,f the canon. about seventy-five yards below our carol), and wrs so(m back for n:ore c?tton. I felt certain then of a nest end shortly after my brother located it in a red fir tree.
