4. NORTH —— 
CENTRAL — —~— 
SOUTH —— 
b 
Ze 
it 
0.8 
0.6 
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I 
0.24] | } 
UU DNINDEAN 
1930 1940 1945 1955 
ROBIN - FOOD 
NOPTERA (esp. ants) 
OPTERA (esp. 
Noctuidae) 
RA (esp. march & 
crane flies) 60 
40 
20 
DPTERA (esp. ground 
S$, Scarabs, click 
s, & weevils) 
TERA (esp. stink bugs a Saar] < 
DPTERA 8 
NIDA 
uw 
PODA e 
forms 5 3 
(sp. grapes, black_ 
, & cherries) 
50 
30 
10 
NO OOOIOD 
FEB MAR APR MAY JUN JUL AUG SEP OCT 
- I.—Food habits data on the robin from the study of Forbes, 
880), Percentages represent the part of the total food identified in 
lachs of several robins examined each month. 
Fig. 8.—Annual variation in 
winter robin populations, based on 
Audubon Christmas counts in three 
regions of the state. Graph line 
shows the number of robins seen per 
party hour. (For information about 
the Audubon Christmas counts, see 
Cruickshank 1970.) 
1965 
icant mortality factor in robin populations, as it is in blue- 
bird populations. Dead robins and reduced populations 
have been recorded in northern Illinois following severe 
wind, cold, or snow, especially in April (Butler 13.0 67 
Blocher 1921, Schafer 1921, and Segal 1960). Roseberry 
(1962) found robins among the dead birds picked up near 
Carbondale following prolonged snow and cold in Febru- 
ary and March. 
VARIED THRUSH (Ixoreus naevius) 
(Fig. 10) 
Because there are at least 16 records of this species from 
14 different localities in the state, its occurrence cannot be 
considered accidental. Only one record was found in the lit- 
erature before 1950 (Fig. 11) and there were four in 1970 
(Armstrong 1970). All records are from northern Illinois 
with the exception of one wintering at Decatur (Lobik 
1957). All dates given fall between mid-December and 
March 30 with one exception (April 26, 1929 at Blue Is- 
land, Bartel 1932). 
The usual pattern of behavior is that a single bird, most 
often a male, will appear at a feeder (or area providing food 
such as crab apples) around Christmas time and remain for 
several weeks. This far northwestern breeder seems to be a 
habitual winter wanderer, occurring fairly regularly in 
northeastern United States and spottily as far southeast as 
the Gulf Coast (Keith 1968). 
