PLAIN TITMOUSE 573 



warmer, north, sun-facing slope where there are live oaks, blue oaks, and 

 digger pines ; and although they forage in the golden oaks on that side 

 of the valley they do not cross to the denser stands of golden oaks which 

 grow on the shaded south slope only a fraction of a mile distant. Up the 

 Merced Cailon the range of the Plain Titmouse, like that of the Brown 

 Towhee, ends abruptly where the Transition Zones commences, at about 

 3300 feet altitude. 



At Pleasant Valley 9 of these birds were recorded in a census of 3i/2 

 hours on February 27, 1916. On May 24, 1915, about 30 were noted 

 during 5 hours spent in the same general territory. In the latter number 

 were 2 broods; if these be assumed to have numbered 5 each, the average 

 for adults would be 4 an hour, more than were recorded during the winter 

 census mentioned. But titmouses are more in evidence in spring; their 

 voices are heard more frequently then, and this probably accounts for the 

 differences in the two censuses. Six or more, all adults, were seen during 

 an hour and a half spent on the hills near Lagrange on May 7, 1919. 

 During most of the year the birds live in pairs, but in summer when the 

 annual broods have been reared, family parties of 6 or 7 may be found 

 rather commonly. 



The Plain Titmouse nests in holes in trees. Old woodpecker holes are 

 used when available, but many, perhaps a majority, of nests are placed 

 in naturally rotted-out cavities. The height above the ground varies accord- 

 ing to circumstances. One nest found near Blacks Creek on May 12, 

 1919, was only 33 inches (830 mm.) from the ground, measured from 

 the entrance, and the nest surface was 6 inches (150 mm.) below that. 

 Another studied in detail near Lagrange on May 8, 1919, was lO^/o feet 

 (3170 mm.) from the ground. Both were in blue oaks. 



This second nest was in the same tree with, and only 17 inches (440 

 mm.) from, that of a Western Bluebird; and there was a Swainson Hawk's 

 nest in another oak 12 yards distant. The titmouse's was in a natural 

 cavity of rather large size. The bottom held a mass of fine dry grasses,, 

 perhaps 4 inches in depth, and on top of this was a heavy felted lining 

 of cow hair and rabbit fur. The top of this mat was 5i/o inches (138 mm.) 

 below the margin of the entrance. There were in the nest 5 half-grown 

 birds and one infertile egg. The young had acquired many of their 

 feathers, though these were still mostly in the feather-sheaths. The finely 

 comminuted remains of such sheaths as had been shed had sifted into the 

 matted hair lining. These young birds would probably have left the nest 

 within a very few days. The other nest mentioned contained three small 

 young. 



For purposes of record and study we wished to collect the entire family 

 of this second nest. The young birds were obtained and two adult titmouses 



