1136 U.S. NATIONAL MUSEUM BULLETIN 23 7 paht a 



In contrast to this previously available information, which suggests 

 a nesting season from late May tln-ough July, we found well-grown, 

 but still dependent, young as early as May 20, which indicates that 

 some birds, at least, start breeding early in May. Despite the fact 

 that we saw young frequently, we were unable to find any nests. 



Nests of Baird's juncos are either on the ground or in low trees. 

 Of eight nests mentioned in Lamb's notes or collected by him, two 

 he described as being "located in [the] leafy extremity of a branch 

 6 feet up in a small pine," and one was "6 feet up, against the trunk 

 in a smaU pinyon pine." Two nests were hidden in depressions in 

 the ground; one was "under a smaU stick" and the other "in a hole 

 in the ground 3 inches back from [the] entrance." Another nest 

 was "placed on the ground among some low flowering weeds." Two 

 nests were "made of fine weeds and grasses, lined inside with horse 

 hair." 



Eggs. — Each of the nests Chester Lamb found in 1929 contained 

 two eggs, and this apparently is the normal complete set. The eggs 

 are whitish with small flecks of dark reddish-brown, most heavily 

 spotted on the large end. 



Food. — In May 1965, most foraging was observed on the ground, 

 among dry leaves and weeds, but one bird was seen feeding on the 

 terminal ends of oak limbs about 20 feet above the ground. One 

 bird tried twice, imsuccessfuUy, to catch an insect (fly?) that was 

 slowly flying about 4 inches above the ground. 



Voice. — The song is described in my notes both as warbler-like and 

 as reminiscent of that of the black-throated sparrow. It is a complex 

 song, and is quite variable. It seemed that the song of every bird 

 was different, and it is possible that individual birds sang more than 

 one song, but that point was not determined. 



Weights. — Weights of two adult males were 17.8 and 16.7 grams; 

 an adult female weighed 16.7 grams. 



Enemies. — Baird's juncos are undoubtedly exposed to all the 

 hazards that beset other ground nesting birds. The only record of 

 predation, however, is in Chester Lamb's notes for July 17, 1929: 

 "Early this morning in the meadow [I] saw a large wild cat [Lynx 

 rujus peninsularis]. It had just despoiled a ground nest of a Baird 

 junco." 



Distribution 



Range. — Baird's junco is resident in the Victoria Mountains (La 

 Laguna, Mount Miraflores) of the Cape district of Baja California; 

 casual downslope to Triunfo. 



