440 BULLETIN 191, UNITED STATES NATIONAL MUSEUM 



nests were in Ceanothus bushes, both living and dead, a 4J^ to 11 feet; 

 12 were in pines at from 6 to 50 feet, only 4 of which were above 15 feet; 

 4 were in live oaks at from 7 to 20 feet ; 3 were in sage bushes at from 

 4 to 4^ feet; 2 were in cypresses at from 7 to 10 feet; and 1 was in 

 a Baccharis bush at 6 feet. In the northern portion of the range, many 

 nests are found in conifers, spruces, firs, and hemlocks, often suspended 

 from the ends of limbs 1 5 to 25 feet from the ground and in plain sight ; 

 but I found two nests near Seattle that were in "spirea" bushes 9 to 10 

 feet up. Nests have been found in eucalyptus and pepper trees, in 

 willow and alder saplings, in Kuntsia and hazel bushes, and probably 

 in a variety of other trees and shrubs. 



Mrs. Addicott (1938) gives a full description of the bushtit's nest 

 and how it is built by the busy pair of little architects; her paper 

 is well illustrated with sketches and photographs. I quote from it in part : 



The nest built by the Coast Bush-tit is an intricate, pendant structure, hung 

 in a concealing clump of leaves of an overhanging branch, and it is built of 

 materials which blend with its surroundings, such as mosses, lichens, oak leaves 

 and spider web. The entrance consists of a hole, usually placed on one side 

 near the top, either above or below the supporting twigs. Above the entrance 

 is the hood which is carefully woven around several twigs and which covers the 

 top of the nest. Below the entrance is the neck which is the passage to the bowl, 

 where the eggs are laid. The nest is entered horizontally, but the passage bends 

 immediately and is vertical in the neck. At the bottom the passage flares to 

 make the bowl. The neck is the slenderest, and usually the thinnest, part. The 

 widest portion is the bowl, and here the walls are much thicker and are heavily 

 lined. These features combined with the thick floor of the bowl, make the latter 

 a warm place for the development of eggs and young. * * * 



The first step in the construction of any bush-tit nest is the building of the 

 rim. This is a delicate circle of nest material bound together with spider web 

 and supported between the forks of a twig or between two adjacent twigs to which 

 it is firmly fastened. This circular rim is almost always horizontal, or nearly so, 

 and in no case which has been observed does this hole ever remain as the final 

 entrance of the nest. It is rather the rim of a preliminary open bag. 



After the rim has been built, nest construction may proceed in either of two 

 ways. In the first and most prevalent method, a small bag, perhaps an inch in 

 depth, is hung from the rim, loosely woven and very thin and delicate. In build- 

 ing, the birds cling to the edge of the rim and hang head down into the bag, 

 adding materials to strengthen and thicken it. After this first tiny sac has been 

 made strong it is stretched and extended from within and then the thin places 

 which result are filled in with more nest material. As the nest becomes longer, the 

 birds enter it head first to carry on the work. After a bird disappears inside, 

 the nest shakes violently and bulges out in place after place as the new material 

 is added in the thin sections. The shaking apparently serves to stretch the struc- 

 ture. Most of the work is done from the inside, but some of the thick parts of the 

 bowl are added to from the outside, the birds dinging to the sides as they work. 

 The nest is now a long pendant bag, open at the top. 



When the hood and final entrance of the nest are built, material is added to 



