LEAST VIREO 267 



part of a courtship performance: "The birds were in willows and 

 sparse brush along a small stream in the hills. One, probably the 

 male, was singing and keeping within one meter of the other, both 

 moving through the low branches, feeding. The singing bird kept 

 its tail spread and frequently gave it a twitch, spreading the feathers 

 still more. Also at intervals the tail was pushed downward to a 

 nearly vertical position." 



James Murdock, of Glendale, Calif., writes to me : "An experience 

 with a least vireo, concerning the stealth with which it sometimes ap- 

 proaches its nest, may interest you. A friend and I watched a pair of 

 birds moving in and out of the willows in a stream bed near Santa Ana, 

 Calif., and we soon felt that we had located the area in which the nest 

 was placed. Time after time we would search this area and find noth- 

 ing. Finally, in desperation, we decided to stand on the outskirts of 

 this area, absolutely still (as nearly as we could manage it) and more 

 or less hidden in the thick branches of the willows. My friend did not 

 succeed in standing very still, but regardless of his movements, we soon 

 saw the bird enter the branches at the usual place. What was our sur- 

 prise to see the bird turn sharply in flight just after it had entered the 

 tree area and fly directly to a branch that was hanging down just over 

 the head of my friend. Then the bird seemed to disappear. The 

 mystery was solved only when we began to search every inch of this 

 branch. Concealed from our view, directly above the spot on which 

 my friend had been standing, was the tiny nest with the bird in it. We 

 were able to touch the bird in the nest and she did not fly. We must 

 have looked at it directly more than 15 times before it could be seen." 



Voice. — Grinnell and Storer ( 1924) give two descriptions of the song 

 of the least vireo, somewhat different from those given for the eastern 

 Bell's vireo : "To one observer the song sounded like this : loe-cher, 

 che we, che we-chey? we cJier, die we, che we, cheey. Each set of 

 syllables was uttered rapidly, with a distinct rest between the two." 

 The other song was uttered by the male while he was following the 

 feeding female. "This song was transcribed on the spot as wretchy, 

 wretchy, wretchy, loretchy, wrcef wretchy, wretchy loretchy, wret- 

 cheur, wreer. The r's here indicate a burred or rolling quality ; and 

 the whole song was, as usual, hurried in its delivery. The question- 

 and-answer inflection was striking." 



Field marks. — The least vireo is decidedly smaller than the other 

 California vireos, except Hutton's, and slightly smaller than the 

 latter. Hutton's vireo is more stockily built, its plumage more fluffy, 

 its movements more deliberate, and its white eye ring and two white 

 wing bars are more conspicuous. The least vireo is slimmer in out- 

 line, it is very active in all its movements and its general coloring is 

 grayish, rather than greenish ; it lives in the low thicket, rather than 



