Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1908-03-17
Two Students After Tramp of
1881 Miles Estimate Num-
Der at 100000.
CROP PROTECTION THE OBJECT
EntomoIogist Forbes Supplies Missing
Link in Bird Study and His
Plan is Adopted.

al ItS pdth, HOW lHtlly DlTuS WOulu IL
enclose? How many of each kind?
How would the numbers differ in
fields of different crops, in different
sections of the state, and at different
seasons of the year? And if such a
capture were made, how could it be
useful to the farmer? That very thing
Ill effect has been done, and the p'ean-
ing and results of it, as obtained from
State Entomologist S. A. Forbes of
Urbana makes story well worth tell
ing.
Thousands of bird stomachs have
been examined, revealing the kind and
quantity of food, and hence whether
the different species work for or
against agriculture, but until we know
OF fields it frequents, at what time of
the year it is principally to be found.
and how long it remains, we can not
tell how much it does, nor where its
operations take principal effect. With
cut this knowledge we can not tell
how much it will pay us to do for or
against any species of bird.
Years ago DR.. Forbes began inves-
tigating the food of birds, and he has
had 10000 birds shot for this purpose.
The United States Biological Survey
same work. In 1905 he became i'm
pressed with the need for bird cen
sus TO go with the food studies and
make it possible to give the farmer q
tue and intelligent reason for fighting
or favoring any species of birds.
First Census on Farm
The first such census ever made
was by Dr. Forbes assistants upon
tie 400 acre stock and grain farm of
tie university in 1905-06 They made
81 visits to this place, investigating 40
acres at a time, and travelling in all
1913 miles upon the farm.
| The total number of birds sighted
was 1914. They flushed only 81 kinds
Of birds. and eight species made up 81
per cent of all the summer birds. Dur
ing the summer, Al per cent of al
were blackbirds. 10 per cent were
English sparrows, II per cent were
cowbirds, 4 per cent meadow-larki
Cthe most valuable bird on the farm
Is per cent mourning doves. and 81
lper cent robins. But this means onl,
one blackbird to ~ acres, sparrow
to two acres, a cowbird to Is acres
a dove to 1G acres, and robin TO 2
lacreS
Combining the stomach analyse
with these census, 211a per cent of tn
more abundant summer birds on thi
farm were more or less useful, A pc
cent of rather doubtful utility, and l
per cent, (the sparrows) definitely il
furious. OF the winter birds. 43 ne
cent were more or less useful. % DC
cent doubtful and 50 per cent inju
, ieus.
: This plan of investigation provin
5 entirely satisfactory, it was adopted
! few months later for bird survey
the entire state
+. Two assistants of DR.. Forbe
: A. o. Gross and A. H. Re
tramped 1881 miles through northern
central and southern Illinois in /:
trips during the year beginning Angus
2S, 1907, identifying every bird upo
T a strip of land $50 feet wide, thus Ia
n ing the first spring, midsummer, ia
n and winter bird census of Illinoi
i They found, during the summer, II,
birds, or an average of practically OF
- IhIFd 1iuino in, yl,a or
: through the summer season. Eigl
n teen per cent of all were Engli
" sparrows On this basis the tot
X summer population of the state. fl
W ured separately for its three division
W numbered nearly 81 million birds,
w which 515 millions were sparrows.
XII Are Reliable Specialists
III These students were acute and
~ liable specialists in observing birt
XII They traversed the state in vario
~ directions, always following straig
* lines, and keeping 80 yards apa
W They made an accurate record of ;
W tirds flushed by them or flying ov
~ the $50 foot strip within 800 feet
XXI front of them. A carefully tested DE
W ometer and a lumber counter" {
W abled them to make record of {
u distance travelled and the number
W PAGES taken over each kind of crop.
al Eighty-five species of birds we
in the summer inspection, b
M 10 per cent of these belonged to t
s. species, as follows: English sparro
81 1.414; meadow-lark, OPS; crow-blat
N bird, 900; mourning-dove, 461; die
W cissel. 393; red-winged blackbird, 81
u prairie horned lark. 296; flicker, 10
SIS robin, 1874; field-sparrow, 1856.
III The English sparrows decreased
per square mile from noi
Wjto south, perhaps because they pref
Mthe vicinity of human dwellings; a
Wlthe population diminishes southwal
w for every 100 in northern Illint
WltEere were but " in central and
W ir southern illinois, But the natl
W birds increased from north 10 sou
W apparently for climatic reasons, in
W ratio of 100, 116, and 129. The sal