CATBIRD 
BREEDING RECORDS 
NESTS OR YOUNG 
@ i950 — 
4 1900-1950 
MH BEFORE I900 
PAIRS OR SINGING 
MALES (JUNE) 
Oo 1950 — 
A 1900-1950 
O BEFORE 1900 
Scale 
190 10 20 30 40 SOMiles 
Fig. 13. — Breeding records for the catbird in Illinois. 
ant of man, and there is an interesting variation from 
north to south in the use of urban residential habitat by 
catbirds (Table 3). In the north this habitat is relatively 
little used and in the south it is the most important 
habitat. The catbird, thus, has at least one expanding 
habitat. 
The catbird is also a forest-edge species (Kendeigh 
1944). In Piatt County, Weise (1951) found no catbirds 
nesting in floodplain or upland forest, but two to three 
pairs per 100 acres in forest edge. In Mason County, 
Gates (1911) considered the catbird a dominant species 
of hydrophytic thickets, and of secondary importance in 
hedges, orchards, and bottomland woods. Nehrling 
(1880) also felt that the catbird favored wet areas, and 
Beecher (1937), Robertson (1944), and others have re- 
corded the species nesting in notably wet habitats. In 
southern Illinois especially we have found catbird nesting 
population to be highest in swampy situations. 
We have summarized the available data on plant 
species used for nesting by catbirds (Table 4). ‘They use 
thorny plants for nest sites, but not to the extent that 
thrashers do. In northern and central Illinois, grape 
(Vitis sp.) is much used by catbirds, not only for nest 
placement, but in nest construction. Barnes (unpublished 
18 
notes) noted that a very high percentage of catbird nests 
contained sizable amounts of grape bark. 
The only information on the size of a catbird’s terri- 
tory in the state is from southern Illinois, where Brewer 
(1955) recorded the area of activity of two nesting pairs 
to range from 0.16 to 0.36 acre. This is much smaller 
than the territories of brown thrashers in central Illinois 
(1.6+ acres, Hensley 1948). Our data also indicate small 
territories for catbirds; we have found active nests (with 
eggs) only 48 feet apart in a southern Illinois thicket. 
Nesting Cycle 
Ridgway (1925), Schantz (1931), and others believed 
that catbirds returned to the same nesting territory year 
after year. Banding records presented by Bartel (1935), 
Lincoln (1927), and Jurica, et al. (1959) tend to support 
this view, as catbirds banded in May and June were re- 
covered in successive years at the places of banding. Bartel 
(1942) also banded a young catbird and recovered it the 
next year in the same area. 
Like the thrasher, the catbird arrives singing in spring. 
Of the song, Ridgway (1889:108) reported that the song 
is conspicuous, sometimes brilliant, but in his performance 
there is too much deliberation, and the general effect 1s 
that he is merely practicing. The catbird’s whisper song 
is especially soft (Schafer 1916). Catbirds mimic some 
sounds (Ridgway 1889:108), and also, like the mocker, 
sing at night (Farwell 1919, Musselman 1932). Singing 
drops off sharply after June, and during July and August 
songs are often subdued and incomplete with few bird: 
singing. The cat call that gives the bird its name is heard 
increasingly later in the nesting season, along with an 
alarm note which we translate as a “chwurk.” 
The nesting season, from the beginning of nest-build- 
ing to the fledging of the last young lasts from about Apri 
28 to September 2 in southern Illinois, and from May i 
to August 24 in the north (Fig. 12). 
One nesting cycle, from nest-building through fledging 
of young, took 29 days at Wilmette, Illinois (Davis 1942) 
but most nestings probably take slightly longer. We have 
known nests to remain empty 5 and 6 days before re 
ceiving the first egg, and have recorded incubation period: 
of 12-13 days for several clutches. Young usually fledgec 
in 11-12 days. Davis (1942) felt that incubation wa' 
carried out exclusively by the female, setting about 2 
minutes and taking off 5. He also reported that both sexe: 
fed the young. 
Data on the plants used for nest sites are summarizec 
in Table 4. Most catbird nests are found at heights be 
tween 4 and 8 feet. Our sample of 85 nests from norther! 
Illinois averaged 5.5 feet in height. Nests further soutl 
were higher, on the average — 6 feet in central Illinoi 
(26 nests), and nearly 8 feet in the south (21 nests). Wi 
have no explanation for this trend. By comparison witl 
the thrasher, catbirds place their nests high. A catbirt 
nest located about 50 feet high in an elm in Peoria Count 
(Loucks, unpublished note) was probably exceptional 
We have found no record of a ground nest for this species 
