70 
THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 
TABLE 3. Rotated principal components pattern from a PCA of 15 plant species composition guilds (n = 27) used to 
model Henslow’s Sparrow and Sedge Wren occurrence. Values are the correlations of the raw variables with each PC 
Highest correlations are in bold. Gram is graminoid. Uppercase abbreviations refer to USFWS Wetland Indicator Status 
(USDI 1988). OBL = obligate wetland, FACW = facultative wetland, FAC = facultative, FACU = facultative upland, and 
UPL = upland. 
Variable 
PC I 
PC II 
PC III 
PC IV PCV 
Gram FAC 
Gram FACU 
Woody FACU 
Gram UPL 
Gram FACW 
Woody OBL 
Forb FACW 
Woody FACW 
Woody FAC 
Forb OBL 
Forb UPL 
Woody UPL 
Forb FACU 
Forb FAC 
Gram OBL 
Proportion s 2 explained 
0.813 
0.804 
0.549 
-0.746 
-0.751 
-0.129 
-0.155 
-0.061 
0.073 
-0.582 
-0.062 
0.169 
0.175 
0.024 
-0.235 
28% 
-0.267 
-0.048 
-0.049 
0.028 
-0.323 
0.095 
-0.152 
-0.114 
-0.090 
0.152 
0.204 
-0.347 
-0.266 
0.174 
-0.200 
-0.117 
0.133 
-0.31 1 
-0.222 
0.000 
0.927 
0.068 
-0.042 
-0.053 
0.871 
-0.117 
-0.033 
0.022 
-0.139 
0.862 
-0.058 
0.240 
0.139 
0.744 
0.186 
-0.353 
0.052 
-0.640 
-0.034 
-0.021 
0.084 
0.055 
0.808 
-0.013 
-0.097 
-0.041 
0.684 
-0.293 
-0.149 
0.140 
0.491 
0.353 
-0.071 
0.069 
-0.050 
0.850 
0.352 
-0.371 
-0.082 
0.512 
12% 
11% 
10% 
9% 
Sparrows were at least tolerant of this cover typ 
during both breeding and nonbreeding season* 
although an adequate level of graminoid cover i 
important for stand occupancy (Brooks am 
Stoufler 2010). Bachman’s Sparrows are oftei 
associated with areas of dense herbaceous cove 
and low shrub cover (Plentovich et al 1998b 
Tucker et al. 2004), but they may be flexible it 
their habitat preferences. Haggerty (2000) con 
ducted a region-wide study across five states anc 
found Bachman’s Sparrow preferences for fort 
cover, vegetation height, and tree density varieo 
widely across regions. 
We found Bachman’s Sparrows used two of the 
FIG. 2. 
SS 6 amon ® 
six clusters managed for RCWs (Dunning and 
Watts 1990, Wilson et al. 1995). Plentovich et al. 
(1998b) also found that not all RCW clusters 
surveyed at sites in Florida were suitable for 
Bachman’s Sparrows. One explanation is the 
relatively small size of many RCW clusters. The 
mean breeding season home-range size of Bach¬ 
man s Sparrow is between 1.5 and 4.8 ha, and 
varies with time since fire, timber age, and 
vegetation structure (Haggerty 1998, Stober and 
Krementz 2006, Cox and Jones 2007). Many, but 
not all, RCW clusters in DSNF are probably too 
small (< 0.5 ha) to be of value to Bachman's 
Sparrows, particularly if the surrounding habitat is 
inadequate. Winter home range size, however, has 
not been well studied. 
There may be several reasons why Bachman’s 
Sparrows avoided bogs. Bogs often contain 
standing water (Folkerts 1982), and some species 
of giound-dwelling birds may prefer drier habi¬ 
tats. Another reason is that most bogs in DSNF 
have either few trees or a closed canopy of pine. 
tands with high tree densities are generally 
^QQs ded by Bachrnan ’ s Sparrows (Haggerty 
, 2000), and open bog stands may luck 
adequate singing perches, which are important 
habitat features (Dunning and Watts 1990, Gobris 
992, Brooks and Stouffer 2010). Perches may 
indicate appropriate habitat, even in winter, if 
