LEAST FLYCATCHER 
BREEDING RECORDS 
NESTS OR YOUNG 
@ 1950 — 
A 1900-1949 
M BEFORE 1900 
PAIRS OR SINGING 
MALES (JUNE) 
OF 1950— 
A\ 1900 — 1949 
DO) BEFORE 1900 
Fig. 40. — Breeding records for the least flycatcher in Illinois. 
Singing male records cover the period June | to early July. 
(Fig. 39). The average clutch size for 11 nests, all having 
either 3 or 4 eggs, was 3.6 eggs. 
The time requirements for incubation and nestling 
life have not been determined, nor are there quantitative 
data on nesting success or productivity. 
Fall Migration 
Records for adult least flycatchers in southern Illinois 
(well south of the breeding range) on July 22, August 4 
(Kleen & Bush 19716), and August 14 (U.S. National 
Museum specimen) indicate how early the fall migration 
of this species begins. The two August specimens were 
both adult females, and the August 4 specimen still 
showed a brood patch and slightly enlarged ovary (2.5 x 
5mm). It was also in worn breeding plumage, though 
showing some signs of the molt on its body. Despite these 
remnant signs of breeding, we believe the bird to be 
definitely a migrant. This seeming haste to inititate the 
fall migration is puzzling, especially as the species’ 
migration is also quite prolonged in the fall. 
Migration of least flycatchers is apparently nocturnal. 
At least 11 specimens (both sexes, adults and immatures) 
have been picked up from bird kills at television towers in 
central Illinois in 5 different years (Brewer & Ellis 1958; 
Parmalee & Parmalee 1959; unpublished records, 1966, 
1968, 1972). The dates of kills for least flycatchers were 
46 
immatures) were killed at two towers in Piatt aj 
Champaign counties on one night, September 20-2 
1966. The peak of the fall migration for the le; 
flycatcher, as for other Empzdonax, cannot — 
determined from our field censuses because of 1 
problem of making specific identifications. The le; 
flycatcher’s fall migration probably regularly extends ir 
October, with records as late as October 9-10 in northe 
Illinois (Ford 1956, Coursen 1947, Mark Swan persor 
communication, 1971), and October 14 for the southe 
region (Cooke 1888). A record for October 29 in northe 
Illinois (Dillon 1968) is an exceptionally late departur 
from September 10 to 29. Four females (two adults, : 
| 
Food Habits 
Almost nothing is known of the food habits of | 
least flycatcher in Illinois. Forbes (1878) examined 
stomachs of leasts, but provided no information on da 
or places of collection. All of the birds had eaten inse 
— Coleoptera were found in 8 stomachs, Hymenoptera 
2, and Lepidoptera in 2. No specific identifications w 
provided. Gault (unpublished notes) examined | 
stomach of a May specimen from Cook County and fou 
it filled with beetles, but here also more spec 
identifications are lacking. 
Clearly, all aspects of the biology of the Ie 
flycatcher in Illinois are badly in need of study. 
EASTERN WOOD PEWEE (Contopus virens, 
(Fig. 41 and 42 
Spring Migration 
The eastern wood pewee is a nocturnal migrant 
Illinois, as indicated by specimens killed at night 
central Illinois television towers.We know of only | 
killed in the spring — on the night of May 27-28, 19 
Whether pewees also migrate by day is apparel 
unknown. 
Returning from the wintering grounds, the first wi 
pewees do not usually reach Illinois until after April 
(Fig. 43), and though there are a number of publis! 
records for the pewee earlier than April 15, even 
central and northern Illinois (Silloway 1902, Hess 19 
Kauffman 1917, Bartel & Reuss 1932, Abbott et al. 19 
Duncan 1934-1935, Smith 1942), we suspect that tk 
records are erroneous or accidental. To some extent tt 
excessively early records for the “pewee” may stem fro 
confusion of names. Particularly in the older literat 
the name “pewee” was often applied to the east 
phoebe. It is also possible that some of the early recc 
were based on “‘pewee” songs uttered by starlings, wl 
are excellent mimics of the pewee. 
Even for southern Illinois, records for the wood pe 
as early as April 12 and 14 (James Funk, and Mic! 
Morrison, personal communications) are probi 
exceptional, and late April or early May arrivals are 1 
representative (Fig. 43, Cooke 1888). In central Illi 
the wood pewee has been detected as early as april 20 
22 (L.B. Hunt personal communication, Smith 19 
