4 Tone ASUS UI BIO UNee SU elaine be lan aly 
been recorded on the Christmas 
Bird Counts. 
The population shift is further 
exemplified by the counts in St. 
Charles County, Missouri where a 
large shift is exibited from year to 
year, whereas in East St. Louis 
the populations were relatively 
stable from 1950 to 1956. These 
counts were open to error as they 
can be made in the most part only 
in those areas accessible by auto- 
mobile while the number of obser- 
vers determines how thoroughly an 
area can be covered. 
In the summer of 1962, I tried 
to check all of the areas of tree 
sparrow population, both former 
and new, in an attempt to extend 
the boundaries of their limited 
range. One bird was encountered 
at Modoc, Ill., along the levee. This 
established a new southeast lmit 
which formerly was Belleville 
(formerly Fulton County, Ken- 
tucky). 
Since Wilhelm’s revision, colo- 
nies have been established in 
Springfield, Beardstown, and 
Quincy as reported by reliable ob- 
servers. Some of the areas in which 
the population had disappeared 
have regained favor with this 
species notably Affton, Grafton, 
Alton, Godfrey and Belleville. 
It is interesting to note that the 
range expansion of this species 
follows the river system rather 
closely. This species has advanced 
up river to Quincy and down to 
Modoc on the Mississippi River. 
On the Illinois River it spreads 
from Hardin to Beardstown, east- 
ward to Jacksonville and Spring- 
field. It has advanced up the Mis- 
souri only to Washington. 
The range extension of the Eu- 
ropean Tree Sparrow has followed 
some rather’ definite patterns. 
When the flocks disperse in the 
spring, the birds scatter widely 
and set up territories. Those birds 
occurring in areas. of highest con- 
centrations push out furthest to 
accommodate the nesting activities 
of each pair within the population. 
This could account for the recent 
(1959-1962) northern penetration of 
the Illinois and Mississippi Rivers 
by this species. Rivers are natural 
migration routes where grain is 
abundant in the bottom lands. The 
great concentrations in Baden and 
St. Charles County could have led 
to their recent penetration some 
one hundred miles up the Missis- 
sippi to Quincy, as well as their 
establishment in Beardstown by 
way of the Illinois River about 
ninety miles. The Jacksonville and 
Springfield populations could have 
spread eastward from the Ilinois 
River, but in this case a cross- 
country invasion from the great 
concentrations in the _ Illinois 
American bottoms, particularly the 
East. St. Louis population, seems 
more likely. The bird discovered 
at Modoc probably is a remnant 
of this population, as well as other 
specimens encountered along the 
levee in recent times. 
The sparse populations charac- 
terizing the urban areas and the 
Southern portion of its Missouri 
range don’t require much more 
area for nesting activities than for 
wintering. The greatest penetration 
in this area up the Missouri River 
60 miles to Washington occurred 
about 1935. At this time, however, 
the population was more concen- 
trated in the southern portion of 
its range due to less habitation by 
the human population. Urbaniz- 
ation as well as population pres- 
sure could have caused the exten- 
sion of their range along the water 
courses. 
Farmland is the preferred habi- 
tat of the European Tree Sparrow 
and its recent penetration includes 
some of the best in the area. 
Their range includes the Missouri 
Delta in St. Charles County, the 
Illinois American Bottoms center- 
