ROBIN 
WINTER RECORDS 
DEC.1—JAN. 31 
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Fig. 7.—Winter records for the robin in Illinois. The three regions 
of the state discussed in the text are shown by heavy lines. 
In June a change to a primarily fruit diet occurs, and 
fruit (much of it wild) is very important through the rest of 
the summer and fall (Fig. 9). In late summer and fall 
(particularly October) we have observed robins feeding 
heavily on wild grape (Vitis sp.), black cherry (Prunus ser- 
otina), Parthenocissus, hackberry (Celtis sp.), dogwoods 
(notably Cornus racemosa, C. rugosa, and C. stolonifera), 
multiflora rose, pokeberry (Phytolacca americana), elder- 
berry (Sambucus canadensis), persimmon (Diospyrus virgi- 
niana), and red cedar (see also Hulse 1912, Bell 1956, and 
Cone 1963). Other fruits commonly recorded as robin food 
are: mountain ash (Sorbus sp.), sumac (RAus sp.), barberry 
(Berberis sp.), bittersweet (Celastrus scandens), holly (Ilex 
decidua), snowberry (Symphoricarpos sp.), pear (Pyrus 
sp.), apple (Malus sp.), and greenbrier (Smilax sp.) (Cooke 
1885, Musselman 1934-1935 and 1963, Holcombe 1936, 
and Pitelka 1936). At least one instance of robin intoxica- 
tion from fermented hackberries has been recorded (Buck 
1936). Forbes’ (1903) only winter specimen (from Cairo) 
contained fruit of mistletoe (Phoradendron flavescens) ex- 
4 
clusively, but local observers felt that winter robin por 
tions in that area depended mainly on wild grapes and 
a failure of the grape crop was reflected in reduced Ww 
populations. Cooke (1885) also noted that robins fed hi 
ly on wild grapes in southern Illinois. 
Forbes (1900) believed the robin to be function; 
controlling cutworm numbers, and Rice (1946) estim 
that robins consumed about five-sixths of the invertel 
population in leaf litter at a forest edge in Champ 
County. 
Charles (1909) recorded that both adults fed the yo 
putting in a 15-hour day in late May, and bringin 
average of 356 pieces of food per day. Lepidoptera I< 
comprised about 50 percent of the total food, with e 
worms (about 29 percent), ants (about 7 percent), Di 
(about 6 percent), and small percentages of Coleor 
Myriapoda, and adult Lepidoptera making up most ¢ 
other half. Earthworms as food for the young have 
been recorded by Mann (1908) and Scherer (1924). 
Longevity and Mortality 
Based in part on northern Illinois banding data, F 
(1945a) determined the average natural longevity for: 
in to be 1.7 years. He estimated the age group compo 
for the population as follows: first-year birds, 53 pe 
second-year birds, 25 percent; third-year birds, less th 
percent; fourth-year birds, less than 6 percent, fiftt 
birds, less than 2 percent; and sixth-year or older bird 
than 1 percent. A sample of 28 returns of robins banc 
northeastern Illinois produced six birds past 3 ye 
age, one past 4 years, and one past 6 years (Dov 
1949). A robin, recognizable because it had white 
feathers, was seen regularly in the breeding season at 
dale in 6 successive years (Tuttle 1927), and Ba 
(1968) oldest banded robin was nearly 5 years olds | 
As to the causes of robin mortality in Illinois, the | 
ture has dealt in detail with only one type—insectici¢ 
soning. Bartel’s studies in Cook County (1960, 1962, | 
are particularly valuable because he studied a bande 
ulation for which he had a long-term population reco! 
established that 85-90 percent of the robin populatic 
eliminated following application of 2 pounds of hept 
per acre for Japanese beetle (Popillia japonica) cont 
year after treatment the robin population had rec: 
only 5 percent, but 2 years after treatment it was bacl 
percent of the pretreatment level (Bartel fide Mu 
1960 and Graber 1962). | 
A robin population was eliminated (as evidenced | 
recovery of dead birds and the disappearance of robin 
established nests) in an area of Iroquois County by t 
plication of 3 pounds of technical dieldrin per acre, 
for Japanese beetle control (Scott et al. 1959). Large 
bers of dead earthworms were seen following the trea 
and this was believed to be the route-source of the t¢ 
in robins (see also Barker 1958). Very high robin m¢ 
from DDT application has also been re 
(Montgomery 1956). 
Severe weather in late winter or spring may bea’ 
