1214 U.S. NATIONAL MUSEUM BULLETIN 237 part 2 



a refuge, as they tended to run beneath the shrubbery and take flight 

 from some distant point. 



Both races of Brewer's sparrow apparently behave similarly when an 

 intruder approaches the nest. Many authors, among them J. G. 

 Tyler (1910) and Grinnell, Dixon, and Linsdale (1930), have com- 

 mented on the apparent reluctance of an incubating breweri to leave 

 its nest. Thus, approaches of less than 2 feet are sometimes possi- 

 ble if no rapid movements are made. These latter authors note that 

 brooding birds driven from the nests fly off silently and sometimes 

 retiu-n to a nearby bush "protesting weakly at the intrusion." 

 One bird retm-ned quickly, and, hopping on the ground mthin 2 

 meters of the intruder, chirped excitedly. When disturbed, taverneri 

 will occasionally remain near the intruder. H. S. Swarth and A. 

 Brooks (1925) observed pairs of excited birds "perched on the tallest 

 bushes, jerking their tails in a manner seen in no other Spizella save 

 monticola." 



Voice. — Brewer's sparrow is said to be vociferous, especially on the 

 breeding grounds, where it often engages in flock trilling. The great- 

 est volume of song is attained in the twiUght and dawn chorus, M'hich 

 on dark days will extend almost to noon, although individuals can be 

 heard from time to time even during the night. W. P. Taylor (1912) 

 writes that in Nevada diu-ing the latter part of May and the first of 

 June breweri is a most vocal species, and can be heard earher than 

 3:00 a.m. and later than 8 p.m. At this locahty some singing con- 

 tinued until at least August 10, though it was certainly not so prom- 

 inent at that date as earher in the season. 



The comphcated phraseology of the song has made schematic 

 representation difficult, and many authors have resorted to a verbal 

 interpretation. F. A. Pitelka (1951) describes the song as weak, 

 monotonous and not very noticeable, while Hartshorne (1956) states 

 it "impfies marked continuity and variety." W. L. Dawson (1923) 

 interprets the song as "weeeezzz, tubitubitubitubitub," which indi- 

 cates its repetitive nature but not the variations in pitch that may 

 usually be heard. 



To H. S. Swarth (1930) the song of taverneri suggests a cicada-fike 

 trill, with many interpolations suggestive of a canary's song and, as 

 with the canary, it was long-sustained. There seemed to be a fairly 

 regular sequence of trills and stops, but it was not a short, definite 

 and unvaried song, as with the golden-crowned and white-crowned 

 sparrows. I. M. Cowan (1946), although not stating whether 

 taverneri' s song is continuous or broken into phrases, gives its duration 

 as 10 seconds. 



At the close of the breeding season the song chorus stops, and the 

 most common notes are an abbreviated song or twittering and slight 



