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344 
THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 2. June 2011 
TABLE I. Structure of Black-throated Gray Warbler Type I songs in southwestern Oregon and northern California. 
The occurrence of B-phrase syllables represents the percentage of songs in which the syllable was present. Brackets indicate 
the two adjacent syllables combine into a single syllable in >50% of the songs in the song form. A question mark indicates 
the occurrence of a syllable but whose relationship to B,_ 5 from the Upper Rogue Valley variants is uncertain. 
Waicrshed/region 
Song variant 
n 
Sequence of notes in 
A-phrase syllable 
Upper Rogue River 
Emigrant 
6 
VT a 
Applegate 
147 
VT 
Caves 
103 
VT, VTT 
Grave 
59 
TV 
Crooks 
44 
VTT 
Diamond Rock 
12 
VTT 
Upper Umpqua River 
Cow 
6 
TV 
Starvout 
11 
TTVT 
Days 
27 
VTTT, TVTTT 
Klamath River 
Humbug 
28 
TTVT, VTTT 
Happy Camp 
3 
VT 
Coast 
Agness 
11 
VT, VTT 
Winchuck 
17 
TVT 
Smith 
3 
TVT 
“ V = vibralo note. T = tonal note. 
% occurrence of B-phrase syllables 
B, 
Bj 
B, 
B, 
B, 
50 
[100 
100] 
83 
33 
99 
99 
97 
99 
81 
79 
99 
75 
99 
66 
100 
100 
100 
100 
88 
100 
100 
98 
100 
100 
25 
25 
[83 
83J 
93 
100 
50 
? 18 
27 
[73 
73] 
100 
93 
93 
78 
?86 
|?89 
782] 
[96 
79[ 
?I00 
7100 
100 
100 
91 
791 
64 
?88 
[100 
100] 
767 
767 
100 
67 
general pattern (2 phrases with the first phrase 
composed of repeated syllables including 1 
vibrato note). However, syllables of the first 
phrase often differed in notable ways, especially 
in the Days dialect of the Umpqua River 
watershed to the north (Fig. 3). This characteristic 
syllable or a variation thereof occurred at least us 
far north as Gales Creek in the northern Oregon 
Coast Range and into central Washington. How¬ 
ever, not every variant sampled in this area 
incorporated this or a related syllable. 
Relationships among variants along the coast 
and the Klamath River were less clear. Coastal 
variants (Winchuck and Smith) shared similar 
syllables in the A-phrase, and the Winchuck and 
Humbug variants from the Klamath River shared 
similarities in structure of the B-phrase. but the 
four variants do not form a clearly related set. The 
Agness variant between the Upper Rogue River 
set of variants and the Winchuck variant on the 
coast shared some similarities with both. 
Distribution and Stability of Variants .^The 
geographic limits of related variants corresponded 
to ridges 1.000-1,200 m or greater in elevation 
above mean sea level. The Siskiyou Mountains 
oriented east-west along the Oregon-Calitomia 
border formed one boundary. The Kalmiopsis and 
Coast Range oriented north-south formed another, 
separating coastal variants from those of the 
interior valleys. Apparently suitable habitat oc¬ 
curred along the Illinois and Rogue river canyon 
that transect the coastal mountains. However, 
variants did not tend to extend through these 
narrow corridors. 
Ridges 700-1.000 m in elevation served as 
partial barriers for the Agness. Caves, and Grave 
variants with limited distribution extending across 
these ridges. Boundaries of variants within the 
regions defined by these ridges did not confonn Ifl 
obvious geographic features. 
Song variation was greatest in the most 
fragmented and geographically limited variants- 
for example, the restricted and isolated Emigrant 
variant included considerable variation among the 
neighboring males (Fig. 4D). 
The Diamond Rock song varied across it-' 
fragmented range, barely qualifying as a distinct 
song (Fig. 4C). Syllables of the A-phrase exhib¬ 
ited clinal changes across the long axis of the 
range, becoming more similar to the Caves variant 
