The Orange-crowned Warblers 



with them; and because of their unceasing efforts in song one gets a 

 rather better impression of the abundance of bird life on the Channel 

 Islands than the facts strictly warrant. Sordida is, of course, a localized 

 race of the V. celata type. That it should be a "saturated" form, follow- 

 ing the analogy of the Island Horned Lark, Otocoris alpestris insularis, 

 seems a little surprising, even to those who know island conditions best. 

 To be sure, moisture is abundant and fogs fairly prevalent in season; but 



so, too, are bright days 

 and open places, inso- 

 much that the Islands 



Upper 



is only 

 on the 



A NESTING HAUNT OF THE DUSKY WARBLER 



are rated 

 Sonoran." 



Perhaps it 

 imagination 

 writer's part, and per- 

 haps it is lack of im- 

 mediate competition in 

 song; but I have fancied 

 that the vocal efforts of 

 V. c. sordida are more 

 varied than are those of 

 the mainland type; and 

 this, although the 

 changing pitch and the 

 ventriloquial quality 

 which characterize the 

 northern bird are less 

 conspicuous. The trill 

 in sordida is rapid and 

 slightly accelerated; but 

 the notes are more open 

 and uniform. The 

 units, too, are so dis- 

 tinct as to simulate the 

 Wilsonia pileolata type 

 of song; and they some- 

 times require careful dis- 

 crimination. The rendi- 

 tion of a "song" occupies 

 only a fraction over a sec- 

 ond, but a good deal can 

 happen in an avian sec- 



448 



