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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 
TABLE 2. Distance (cm) of search movements of arboreal insectivorous migrants at Gulf Coast stopover sites in 
spring, 1993-1995. Data under “Fly” were within patch flights and only recorded in 1994 and 1995. Nomenclature for 
species codes is in Table 1. 
YBCU 
ACFL 
EAWP 
RCKI 
BGGN 
WEVI 
BHVI 
YTVI 
PHVI 
REVI 
BWWA 
GWWA 
TEWA 
NOPA 
YWAR 
CSWA 
MAWA 
MYWA 
BTNW 
BLBW 
BBWA 
CERW 
BAWW 
AMRE 
PROW 
WEWA 
COYE 
HOWA 
CAWA 
SUTA 
SCTA 
Search movement 
Hop 
Flutter 
Mean ± SE 
n 
Mean S SE 
„ 
65 
22.7 ± 1.7 
24 
65.8 ± 6.2 
44 
3 
23.3 ± 6.7 
0 
21 
4 
10.5 ± 5.1 
0 
0 
22 
83 
12.3 ± 9.0 
65 
25.7 ± 1.5 
67 
27 
16.8 ± 4.2 
17 
23.8 ± 2.9 
27 
46 
15.5 ± 2.0 
36 
39.7 ± 3.6 
33 
8 
20.6 ± 4.2 
5 
42.0 ± 5.8 
12 
19 
17.3 ± 2.8 
8 
38.8 ± 4.8 
10 
25 
11.5 ± 1.4 
11 
35.5 ± 5.3 
26 
156 
13.2 ± 0.8 
110 
38.2 ± 1.6 
76 
40 
11.4 ± 1.1 
26 
31.0 ± 1.8 
21 
15 
8.0 ± 1.1 
14 
33.6 ± 3.6 
9 
74 
yC 
1+ 
o 
oo 
39 
29.1 ± 1.8 
45 
25 
10.4 ± 1.6 
10 
22.5 ± 4.0 
30 
21 
11.4 ± 1.8 
20 
36.5 ± 2.7 
12 
63 
13.1 ± 1.2 
40 
32.0 ± 2.8 
26 
126 
12.7 ± 1.4 
90 
29.1 ± 1.2 
71 
140 
9.5 ± 0.6 
101 
28.9 ± 1.3 
170 
52 
10.3 ± 1.1 
41 
28.4 ± 2.2 
36 
21 
12.0 ± 1.8 
7 
25.7 + 3.2 
29 
126 
10.2 ± 0.6 
71 
35.5 + 4.1 
102 
D 
11.2 ± 1.3 
7 
31.4 + 4.0 
11 
86 
11.2 ± 2.4 
41 
31.7 + 2.4 
43 
45 
12.8 ± 1.3 
20 
35.5 ± 2.9 
38 
23 
12.0 ± 2.6 
22 
29.5 + 3.2 
15 
39 
10.9 ± 1.3 
24 
40.0 ± 3.6 
23 
30 
17.1 ± 3.4 
12 
28.3 + 4.4 
7 
43 
16.2 ± 2.0 
17 
36.2 + 3.3 
S| 
18 
8.7 ± 1.2 
3 
26.7 + 3.3 
11 
9 
10.6 ± 2.5 
2 
32.5 + 17.5 
9 
15 
12.0 ± 2.0 
7 
57.1 ± 9.2 
20 
Fly 
Mean : SE 
251.8 ± 24.7 
341.0 l 76.4 
523.6 ± 100.1 
97.2 l 9.6 
84.3 ± 8.6 
115.2 ± 15.5 
96.7 ± 16.7 
108.0 ± 13.5 
113.5 ±20.7 
121.3 ± 10.6 
81.0 + 7.7 
80.0 ± 8.8 
92.0 + 13.7 
72.5 ± 5.8 
111.9 ± 18.7 
84.6 ± 11.4 
128.9 ± 7.7 
80.0 ± 5.2 
74.1 ± 9.4 
98.3 ± 7.7 
152.7 ± 40.4 
122.6 ± 22.4 
106.6 ± 18.7 
113.3 ± 13.5 
129.6 ± 25.0 
165.7 ± 60.9 
190.0 ± 19.0 
95.5 ± 23.4 
344.4 ± 88.4 
161.0 ± 22.2 
subgroup was characterized by high search rates 
(Table 1). 
Factors Affecting Search Movements of War- 
Mers and Vireos .—Warblers used different fre¬ 
quencies ot .search movements among sites, 
between plots, presence and absence of vine 
tangles, and high and low migrant density (P < 
0.001, Table 3). Vireos used different frequencies 
of search movements between presence and 
absence of vine tangles (P < 0.05. Table 3), and 
between foraging solitarily and foraging in Hocks 
(P < 0.001). 
Four logistic models were built due to different 
amounts of missing data for each variable. The 
best fitted models contained some higher order 
interactions for warblers, whereas two-factor 
interactions appeared to be sufficient for vireos 
(Table 4). The model indicated that environmen¬ 
tal and social factors influenced frequencies of 
search movements of warblers more strongly than 
those ot vireos. In particular, warblers that 
foraged in areas with vine tangles and in the 
control plot of Hackberry Ridge tended to use 
more hops than flights. Warblers took more hops 
when searching solitarily during periods of lew 
migrant density, especially at Smith Point. In 
contrast, warblers used more flights when lorag- 
ing in mixed flocks, in areas without vine tangles, 
in the disturbed plots, especially at Grand Chenier. 
More hops were used by vireos while foraging 
solitarily at Smith Point, and more flights were 
used in flocks at Grand Chenier. The generalized 
