Illinois are in general agreement with those of McCabe 
for Wisconsin. The song of Illinois breeding populations 
(willow flycatcher) is the so-called “fitz-bew” type, and 
sounds the same in all regions of the state. Each student 
seems to have his own phonetics for this song (McCabe 
1951), and though we have used the more or less 
standardized phrase “fitz-bew” in referring to the willow 
flycatcher song, we prefer our own version of the 
phonetics (“pit-beer” or “fitz-your”). To us the song 
seems to have an “r’ ending. This song phrase is very 
often preceeded by a quick, angry note — frit sor 
“creet,” as McCabe has described it. This “frit” note may 
or may not be part of the song. Sometimes it is the only 
note we hear from territorial birds, and it may be uttered 
over and over again, with pauses between notes. Thus, 
uttered by itself, it seems more like an alarm note than a 
song. In conjunction with the usual song phrases, this 
“frit” note is usually uttered only once (sometimes two 
and rarley even more times). If it is considered to be part 
of the song, then the song may have from two to four, or 
even more phrases, but usually it is either “pit-beer” (the 
basic song) or “frit — pit-beer’ with a slight pause 
between the first and second phrase. When we record the 
song and play it back to nesting birds they almost 
invariably respond quicky by approaching our position. 
Often the recording does not induce singing, but only the 
“frit” call note, which suggests that it is an alarm note. 
Another note often heard from Traill’s is a rather soft 
“whit,” or “whip” as McCabe (1951) designates it. This 
also seems to be an alarm note for nesting birds, but it is 
also uttered frequently by unidentified migrant 
Empidonax flycatchers, and we do not know that it is 
exclusively the vocabulary of Traill’s. 
There are no published data on the time 
requirements for the nesting cycle of Traill’s flycatchers 
in Illinois. One northern Illinois nest that we observed 
was completed from an early stage of construction in 5 
days, before the first egg was laid. Another nest which 
lacked only a lining went 4 days before the first egg was 
laid. The incubation and nestling periods combined for 
one nest that fledged four young in northern Illinois was 
27 days. From these data, one nesting cycle for a Traill’s 
nest with four eggs would require about 35-36 days. 
Goff’s (1932) data indicated that nestling life was at least 
13 days. There are few actual nest records for southern 
Illinois, and essentially no data on the nesting cycle for 
that region. 
Traill’s nests are either built in an upright fork of a 
shrub or tree, or saddled on a horizontal branch (Fig. 32 
and 36). According to Silloway (1894), Willard (1898), 
and Loucks (unpublished notes, 1889), Traill’s flycatcher 
nests are made of grayish bark fibers, dried weed stems, 
fine grass, feathers, and gossamer, with a lining of fine 
grass, horse hair, and feathers. Nests of more recent years 
generally lack the horse hair. The nests often have a 
silvery appearance (Fig. 36), and resemble nests of the 
yellow warbler (Dendroica petechia), and goldfinch 
(Spinus trist?s). We have seen one Illinois nest (Fig. 36) 
that closely resembled the alder type, as illustrated by 
Stein (1958). The variation in nest structure that we saw 
42 
in a single population in northwestern Illinois ne; 
Savanna (Fig. 36) was as great as we have encountered | 
the entire state. 
Egg laying by Traill’s flycatchers has been recorded 
central Illinois between June 3 and July 21, and | 
northern Illinois between June 11 and July 27 (Fig. 34 
The peak of laying occurred between June 11 and 19 
central Illinois (Fig. 34) and is apparently only slight 
later in the north (Beecher 1942). 
Data from the literature, old museum records, ar 
our own notes on 48 Traill’s flycatcher nests with eg 
show that the clutch size in central and northern Illinois 
almost always either 4 eggs (about 70 percent), or 3 eg 
(about 30 percent). The average for all clutches was 3 
eggs with no significant difference between central ai 
northern Illinois nests. In central Illinois, Strumbe 
(1883) also found that most Traill’s nests (65 percer 
received 4 eggs, but Silloway’s (1894) data showed 
predominance of 3-egg clutches (76 percent of all ne: 
with eggs), perhaps reflecting annual variation. In 18 
and 1886 in Bond County, P.W. Smith, Jr. found at le: 
two nests with 5-egg clutches (Chicago Museum 
Natural History Set Nos. 9386 and 9387), but such lar 
sets must have been exceptional even then. Strumbe 
(1883) also reported a nest with 7 eggs, apparently t 
work of two females. 
Traill’s flycatcher must be very uncommot 
parasitized by cowbirds in Illinois, as we know of but o 
other record (Poling 1889) than the one reported 
Friedmann (1963). 
We see no evidence that Traill’s flycatchers try ! 
more than one brood. Though the egg-laying curve : 
central Illinois shows minor peaks in late June and Ji 
(Fig. 34), these peaks probably represent re-nestit 
following nest failures, as they are not spaced adequat 
to be second broods. Silloway (1894) also believed tl 
only one brood was reared. 
There are no published data on nesting success 
productivity for any Illinois population of Trai 
flycatcher. We have histories on only 16 nests, mainly 
northern Illinois in 1968, and they had poor success: 
percent of nests (27 percent of eggs). Causes of n 
failure were unknown, but most nests failed in the ¢ 
stage. A nest that Goff (1932) observed lost two of its fc 
young ina windstorm, but ultimately the remaining t 
were successfully fledged. Gross (1925) mentioned that 
found high mortality (in three out of four nests) 
nestling Traill’s flycatchers in central Illinois from he 
mite infestations. 
Fall Migration 
The problem of field identification of sil 
Empidonax flycatchers has already been discussed (in 
introduction and in the section on the yellow-bell 
flycatcher) and we have relied primarily on captured 
collected specimens for the fall graph points in Fig. : 
In central Illinois Varner indicated, apparently fr 
netting observations, that the peak of the Traill’s — 
migration came in late July and early August (Fa 
1966b, 19686), but other observations indicate 
