| S2 Page 51Collector: Grinnell - 1925
Location: Mineral
Date: June 28
Page Number: 2505
the above reduced plan has been accurately
copied, has been carried with me in my note-book
bag up to the present moment, and on it from
time to time have been located positions of nest
as found or of "centers of interest" (sometimes the
"singing trees") of the birds whose nests we have not
succeeded in finding. The close proximity
of the tract studied to our camp has made it
possible to devote many odd minutes to searching
out nests; and in addition, of course, we have directed
concentrated attention upon it for an hour at a
time, again and again. Mrs. G. has been specially
devoted to the problem, and more than half the actual
nests located were found by her.
My "paces", averaged from a series of steps in a
dusty place, were found to be 32 inches long. Therefore
each side of our plot was 6400 inches long; 6400 x
6400 = 40,960,00 [sic] sq. in; divided by 144 = 284,444 sq. ft.;
this divided by 43560 [= sq. ft. in one acre] = 6 1/2 acres, in
the plot.
It will be seen that, in this 6 1/2 acres, there were 24
breeding pairs of birds, of 14 species - or not quite
4 pairs of birds to the acre. Undoubtedly, this
is a maximum census figure for the whole
region; while thousands of acres will equal
this, other thousands of acres (above canadian
zone, and very dry parts of Transition and
Upper Sonoran) will average scarcely one pair | S2 Page 51Collector: Grinnell - 1925
Location: Mineral
Date: June 28
Page Number: 2505
the above reduced plan has been accurately
copied, has been carried with me in my note-book
bag up to the present moment, and on it from
time to time have been located positions of nest
as found or of "centers of interest" (sometimes the
"singing trees") of the birds whose nests we have not
succeeded in finding. The close proximity
of the tract studied to our camp has made it
possible to devote many odd minutes to searching
out nests; and in addition, of course, we have directed
concentrated attention upon it for an hour at a
time, again and again. Mrs. G. has been specially
devoted to the problem, and more than half the actual
nests located were found by her.
My "paces", averaged from a series of steps in a
dusty place, were found to be 32 inches long. Therefore
each side of our plot was 6400 inches long; 6400 x
6400 = 40,960,00 [sic] sq. in; divided by 144 = 284,444 sq. ft.;
this divided by 43560 [= sq. ft. in one acre] = 6 1/2 acres, in
the plot.
It will be seen that, in this 6-&-1/2 acres, there were 24
breeding pairs of birds, of 14 species - or not quite
4 pairs of birds to the acre. Undoubtedly, this
is a maximum census figure for the whole
region; while thousands of acres will equal
this, other thousands of acres (above canadian
zone, and very dry parts of Transition and
Upper Sonoran) will average scarcely one pair |
EN