Fig. 36. — Variation in nest structure in a single population of Traill’s flycatchers in Carroll County. The population occupied lowland wil 
habitat, and was of the “fitz-bew” (willow) song form. Nest at right resembles alder flycatcher nest. 
creeks, and lakes, or willow clumps in swampy places, 
and added that the species has adapted to orchards, city 
parks and cemeteries as well as trees and shrubs along 
country roads. Ridgway (1889) in the south and Barnes 
(1890) in central Illinois both considered Traill’s (willow) 
flycatcher to be especially an orchard species, yet the 
later statewide censuses indicated that Traill’s flycatchers 
were not at all common in Illinois orchards (Forbes & 
Gross 1921, Graber & Graber 1963). The Ridgways 
(1889, 1915, 1923) also had Traill’s flycatchers nesting on 
their suburban estate in southern Illinois one season 
(Table 6) and suggested that the species was quite 
tolerant of humans. Loucks (unpublished notes, 1889) 
and Goff (1932) both found nests in cities (Peoria and 
Rockford) but there is probably no urban population of 
Traill’s flycatcher in Illinois now, perhaps because cities 
have changed in character a great deal since the 1930's. 
During the nesting season, we have almost always 
found Traill’s flycatchers in open (nonforested) country in 
the following situations: (1) willow clumps in low-lying or 
flat land — stream bottoms, drainage ditches, marshes, 
etc., (2) upland shrub areas, and (3) roadside shrubs and 
hedges, both upland and lowland. In southern Illinois 
south of the latitude of Jackson County we have found 
breeding Traill’s flycatchers only in lowland habitat, not 
in the ample areas of shrub-covered hills, a situation used 
regularly by Traill’s to the north. On strip-mined land, 
Karr (1968) found good populations of Traill’s in central 
Illinois (Table 6), but Brewer (1958) found none in this 
type of habitat in southern Illinois. There are no 
measurements of Traill’s flycatcher populations for 
40 
southern Illinois. In lowland willow clump habitat 
Cook County, Herbert Stoddard estimated the June |! 
population of Traill’s flycatchers to be 25-30 pairs © 
square mile, the equivalent of 8-9 birds per 100 ac 
(Ford 1956). Traill’s flycatchers are usually absent fre 
or at best uncommon, in the forest edge habitat; W 
(1951) recorded 2 birds per 100 acres in forest edge 
Piatt county. 
Hedgerows of osage orange were often considered 
important habitat for Traill’s flycatcher. Silloway (18 
and Willard (1898), respectively, defined the favo 
habitat to be untrimmed hedges of two to four seas 
growth, and hedges not more than 15 feet tall. 
west-central Illinois (Knox County) Harold M. Holli 
(unpublished notes, 1942) recorded six pairs of nest 
Traill’s flycatchers in about one-fourth mile of os 
hedge (48 birds per mile). In east-central Illinois (F 
County) we found much lower densities in about 5 lin 
miles of osage hedge — four pairs in 1958 (1.5 birds 
mile), and three pairs in 1959 (1.2 birds per mile). ¢ 
searches of hedgerows in other areas of Illinois have lec 
to believe that the population densities observed in H 
County are quite representative of recent population 
Traill’s in this habitat. We have seen no population | 
compared with the 48 birds per mile observed 
Holland, yet we believe his observations to be true 
feel that all of the observations indicate a general dec 
in population of Traill’s flycatcher over the years. 
have already mentioned the change in orct 
populations. Where we found low populations 
east-central Illinois hedges, Hess (1910), like Hollan¢ 
