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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 
t Arbutus menziesii), and California black oak ( Q . 
kelloggit). They attain their highest abundance in 
areas where canyon live oak {Q. chrysolepis) is 
most common and are less abundant or absent in 
riparian areas where white alder {Aims rhombi- 
folio) and bigleaf maple ( Acer macruphyllum) are 
common. They occur most often in riparian areas 
along the coast dominated by red alder (A. rubra) 
and bigleaf maple. 
Data Collection and Analysis.—We distin¬ 
guished Type 1 and II songs of Black-throated 
Gray Warblers based on the context in which they 
were delivered (Specter 1992). Use of Type I and 
Type II songs by Black-throated Gray Warblers in 
distinct contexts coincides with that of oilier 
wood-warblers with form-encoded songs. 
We systematically searched the accessible 
roads in appropriate habitat between 1998 an 
2007 recording Type I songs of Black-thru^ 
Gray Warblers with a Sony TCD5 PwUcm«» 
recorder coupled with a Sennheiser u 
■ ME-62 
until 
microphone in a 61-cm parabolic reflector 
2004. We used a Marantz PMD660 
beginning in 2004 coupled with a Sennheiser M • 
62 microphone in a 61-cm parabolic reflect'*' 
Type I songs were recorded between 16 April an 
4 July each year with most sampled beW^" 
sunrise and the attenuation of singing about 1 
