TABLE 6. — Breeding populations of Traill’s flycatchers in various Illinois habitats. 
Birds Per 
100 Acres“ 
Habitat 
ly shrub 21 38 1966 
ub grown areas 15 7 1957 
17 6 1958 
: 15 7 1957 
ian residential 8 25 1915 
kmpy prairie 64 6 1942 
irshland 29 3 1957 
land second growth hardwoods 56 4 1944 
Years 
Type of 
Census 
Region or 
Reference 
County ioe 
Nest Vermilion (C) Karr 1968 
Strip North Graber & Graber 1963 
North 
Central 
Nest Richland (S) Ridgway 1915 
Nest Sangamon (C) Robertson 1942a 
Strip North Graber & Graber 1963 
Nest Sangamon (C) Robertson 19446 
_<_<__ 
_ 4 All figures were converted to read birds per 100 acres (territorial males or nests X 2). 
ie cncral Illinois, found Traill’s to be an “abundant” 
ecies in hedgerows and orchards. We cannot explain 
change. In addition to the declining population 
sities in hedgerows, the hedges themselves are rapidly 
ing destroyed. There is no evidence to indicate that 
aill’s populations in the lowland willow habitat have 
dergone declines similar to that of the hedge 
pulations. 
The specific identity of the Traill’s flycatchers that 
st in hedgerows is something of a mystery. This 
pulation has largely disappeared in recent years, and 
2 song form was apparently never recorded. From the 
en nature of the habitat and the geographic range we 
d expected the hedgerow population to be willow 
catchers, but nests and eggs of Traill’s flycatchers in 
> State Museum collected by H. M. Holland from 
dgerows in west-central Illinois are not typical of the 
llow flycatcher. These specimens show some 
aracteristics (e.g. whitish, finely spotted eggs; coarsely 
astructed nests) of the alder flycatcher. These features 
> highly variable in willow flycatcher populations, 
wever, and we suspect that the hedgerow populations 
I prove to be willow flycatchers. The question needs to 
resolved with careful study soon, before the hedgerow 
catchers disappear completely. 
The list of plants recorded as nest sites for Traill’s 
-atchers in Illinois (Table 7) is probably incomplete. 
st nests have been recorded in osage orange and 
lows. The high number of nests recorded in osage 
‘ticularly is probably not representative of the actual 
tribution of nests by plant species, but more likely 
lects the fact that hedges were convenient places for 
ogists to search for flycatcher nests, especially in past 
‘ades. We do not know how the state population of 
aill’s is distributed by habitat. 
On the heights of Traill’s flycatcher nests Silloway 
94) and Willard (1898) agreed that nests in 
‘t-central Illinois were usually 3-10 feet high, rarely 
her. Records of nest height, including our own, show a 
ige from 3 to 25 feet, with the greater height being 
¢. Twenty-three nests in northern Illinois averaged 6.2 
tin height and 37 nests in central Illinois averaged 6.6 
t. 
Territory size for the Traill’s flycatcher has 
apparently never been measured in IIlinois. The clumps 
of shrubs that serve as nest sites are often surrounded by 
acres of open-field habitat of one sort or another, so that 
nesting pairs are often naturally spaced by the vegetation. 
Neither the minimum distance between nests nor the 
spacing of nesting vegetation has been measured 
precisely. 
Nesting Cycle 
There are no published banding data to show homing 
by Traill’s flycatchers in Illinois. 
Silloway (1894) rarely found Traill’s flycatchers on 
their territories in Macoupin County before the second 
week of June, and we have observed equally late or even 
later arrivals (early July) of nesting Traill’s flycatchers to 
hedgerows in east-central Illinois. 
Much has been written about the variation in song of 
Triall’s flycatchers (see especially reviews by McCabe 
1951, and Stein 1963). Though we have never witnessed 
the song flight described by McCabe, our observations in 
TaBLe 7. — Plants used by Traill’s flycatchers as nest sites in 
Illinois. 
Number 
of Nests 
(Total 73) 
Species 
Osageorange (Macliura pomzjera) maaan ern: 
Willow, (Salzx:sp2) tea pemete ciate cue teh on are ence os 
Mulberry, (Mortis:sps) prunes cr eaters eit on ears 
Dogwood(Gornustdmumumond 11) pene ee 
Elderberry (Sambucus canadensis) 
Maple (Acer negundo, and sp.) 
AlderGdlitus sp:) em erae skewer ioe sy rain erected orcas 
ApplecMalusispr) sre meu eer ee ere eae enc: 
Basswood (iziden spe) sewer eer eit are eran eee 
Elm (Ulmus sp.) 
Grape) ((V2tts'sp.) moran rer, ork a oem aii cies evita cre slarsnc 
ls EnMadnoran (Cit EPOG Os) on oaomnovncbosmnuvoocouadenor 
Hazel (Corylus americana) 
Honey locust (Gledztsza triacanthos) 
Honeysucklel(con7ce7.a sp.) meen eee Tee eet 
Plum (Prunus sp.) 
Shingle oak (Quercus tmbricaria) 
ee ot 
41 
