454 BULLETIN 191, UNITED STATES NATIONAL MUSEUM 



Sierra de la Laguna. It is a sedentary species, of which each individual 

 bird probably spends its entire life within a very limited area, for Mr. 

 Frazar noticed no marked seasonal variations in the number of its 

 representatives at any of the localities which he visited." 



Nesting. — Mr. Brewster (1902) writes: "A nest found on May 24 

 in the top of a small pine about eight feet above the ground, on the 

 Sierra de la Laguna, is similar in shape to the nests of P. m. calif ornicus 

 and P. plumbeus. It is nine inches long, with a diameter varying from 

 two to two and one half inches. The entrance hole is in one side near 

 the top. The walls are composed of small, dry leaves, fern-down, catkins, 

 spiders' c.ocoons, yellowish usnea and grayish lichens, all these materials 

 being felted into a thick, tenacious fabric of a generally mixed brown and 

 grayish color. There were no eggs, the nest being not quite finished 

 when taken." 



There is a set of three eggs in the Doe collection. University of 

 Florida, that was collected by J. Stuart Rowley near Miraflores on 

 May 3, 1933. The nest was in an "oak-like tree," about 6 feet from 

 the ground, and was made of mosses, fine downy fibers, and feathers. 



Eggs. — The eggs of Grinda's bush-tit are indistinguishable from those 

 of other bushtits. The measurements of eight eggs average 13.5 by 10.1 

 millimeters; the eggs showing the four extremes measure 14.2 by 9.9, 

 11.5 by 10.1, and 12.2 by 10.4 millimeters. 



Plumages. — Mr. Brewster (1902) describes the juvenal plumage as 

 "differing from the adult in being ashier beneath, with a decided 

 purplish tinge on the sides; the back paler bluish, the crown light 

 purplish brown; the outer tail feathers with their outer webs ashy 

 white to the shaft; the secondaries and wing coverts edged and tipped 

 with grayish or rusty white." 



He says that a bird in "first winter plumage," taken November 28, 

 is "similar to the young just described, but with the cjown deep 

 purplish brown; the back darker or more slaty than in the adult; the 

 wings and tail more bluish; the outer tail feathers with exceedingly 

 narrow light margins on their outer webs." It seems to me that this 

 bird, which I have seen, is an adult in fresh autumn plumage, as it 

 does not have the juvenal tail, described above; the postjuvenal molt 

 does not involve the flight feathers, and, if this were a first winter bird, 

 it should still have the juvenal tail. 



I have also examined the molting specimen he refers to, taken July 28, 

 which is also evidently an adult. Adults apparently have a complete 

 post nuptial molt, beginning in July, and they are darker and more 

 richly colored after this molt. 



In all its other habits, food, behavior, and voice, it probably does not 



