Tarte 1.— Plants used by loggerhead shrikes as nest sites 
in Illinois. 
Percent of Total Nests 
Species North and 
i Central OULD 
(89 Nests) (55 Nests) 
Osage orange (Maclura pomifera)..... 88 11 
Red cedar (Juniperus virginiana)...... a. 20 
Rose (Rosa multiflora and sp.)...-.-.- ae KS 
Sassafras (Sassafras albidum).......-- - 9 
Japanese honeysuckle (Lonicera 
POMC) ire sek otra wey te ee 
Hawthorn (Crataegus sp.)....--+-+--- 3 
Apple and crabapple (Malus ON Roh 5.3 i 
Cherry and plum (Prunus serolina and 
GIDE) oat ae a) Remar lo ame 2 4 
Grape (Vitis spi)... 2. or eee = 6 
Elm ( Ulmus sp. Joce .2= oe > vs 
S 
Pear (Pyrus COMMUNIS) + vse a eee ha 4 
Honey locust (Gleditsia triacanthos)....  .- 4 
Oak (Quercus sp: )iiiee 22 eet as 2 
Greenbrier (Smilax sp.)......++++++> 2 
Virginia creeper (Parthenocissus 
quinquefolia) by ey ee eee hay MR are reese 2 
Pine (Pinus spi) 6 ep ge ee 2 
Box-elder (Acer negundo).....-.+-+++ x 2 
Poplar (Populus sp.)....-+++ 20805085 1 
@ 
12 
hf 
rw) 
8 
NUMBERS OF NESTING PAIRS OF SHRIKES 
top) 
1957 I959 I96I I963 I965 
Fig. 6.— Number of pairs of shrikes found nesting on a 
36-square mile agricultural area in Ford and McLean counties 
(east-central Illinois), 1957-1966. Nearly all nests were in 
osage orange hedges. 
8 
and a very rapid decline to near zero between 1957 and 
1965 from causes unknown. It is possible, of course, that 
this change is temporary, but as of 1972 we have seen no 
sign of recovery by the shrike population. 
Nesting Cycle 
The song and call notes of the loggerhead shrike are 
highly varied and interesting, with both sweet notes anc 
(more often) harsh, guttural notes, both somewhat re. 
sembling those of the mockingbird (Ridgway 1889). The 
shrike is not a persistent songster and its vocalizations art 
not as well known as those of other common species. Wi 
have seldom heard the song and have no data on thi 
seasonal periodicity of singing in this species. 
Among Illinois songbirds, the loggerhead shrike is ai 
early nester, but Strode’s (1918) statement that nestin: 
(in central Illinois) may begin in early March is ne 
literally true. Musselman (1937) observed completel 
built shrike nests on March 20, 1936 in central Illinoi 
and even this is probably early for the region. Cook 
(1888) believed that shrikes began mating in the § 
Louis area the day after they arrived (March 22) fror 
the wintering grounds. During Gault’s (unpublishe 
notes) many years of observation in northeastern Illino 
the earliest date on which he recorded a completed ne 
was April 8, while April 16-21 were more typical dat 
for this stage in the nesting cycle. 
The earliest laying dates recorded are March 24 f 
southern Illinois, April 3 for the central region, and Ap: 
15 for the north. The peak in egg production comes 
early April in southern Illinois, and in the latter half 
April in central Ilinois (Fig. 4). There are no comp 
rable data for northern Illinois. 
The nests are superficially like thrasher nests, ber 
coarse, bulky structures made of sticks, weed stems, a’ 
grass. However, shrike nests are almost always veé 
warmly lined with feathers or fur, or both (Fig. 
Nehrling 1881, Blocher 1933). There are few reco! 
to indicate the time requirement for nest constructi 
by loggerhead shrikes. Gault (unpublished notes, 190 
observed a nest under construction and/or waiting 
eggs 11 days in northern Illinois, and in southern Illin 
we have recorded nest-building periods of at least 5d 
and 7 days, both nests having been partly completed wi 
found. Five nests in central and southern Illinois I 
incubation periods of 17 days, and the nestling life 
two nests in southern Illinois was 16 and 17 days. at 
the time requirement for one nesting cycle for a nest \ 
six eggs is about 45 days. 
Eaton’s (1878) statement that the loggerhead sh1 
rears two broods (northern Illinois) is not borne out 
our egg-laying data, at least for the population a 
whole, Double-broodedness, if it occurs, is the except 
rather than the rule in Illinois. 
Most shrike nests in Illinois receive clutches of 
eggs, though clutches of seven eggs and five eggs are 
uncommon (Table 2, Strode 1918, Hess 1910). In 
County Blocher (1933a) found the usual clutch to be 
