1144 U.S. NATIONAL MUSEUM BULLETIN 237 part 2 



Specific sites for the 26 nests I studied at Churchill were of three 

 types: 



1. Dwarf willow-birch thickets — 20 nests in tussocks of grass or 

 depressions in the ground at the base of shaggy bushes, concealed by 

 dry grasses and dead branches. 



2. Open tundra, near patch of brush — four nests in depressions in 

 mossy hummocks, concealed by grasses or semiprostrate shrubs. 



3. Spruces at timberline — one nest at base of stunted spruce on 

 open tundra; one nest 5 feet up in a small spruce under overhanging 

 branches, built on the remains of an old redpoll nest. 



All but the last of these were on or within a few inches of the ground. 

 MacFarlane (1891) who examined more than 200 nests in the Anderson 

 River valley, found most of them on the ground, but a few in dwarf 

 willows 1 to 4 feet high. 



The nest is usually built in three layers: an outer shell 20 to 40 

 millimeters thick, composed of heavy grass and weed stems, rootlets, 

 bits of moss, lichens, shreds of bark, and an occasional leaf or twig; 

 an inner coat of fine, dry grass stems, about 10 milhmeters thick; and 

 finally a soft lining of ptarmigan feathers. Generally the nests are 

 compact, well-built, rather heavy, and open to the sky, though a few 

 open at the side. One found in a deeper depression lacked the outer 

 shell almost entirely and was hghtly and loosely woven. The lining 

 feathers, ranging from 29 to 152 in number, were frequently woven 

 into the inner shell. Other materials than ptarmigan feathers may 

 be used for linings — five nests had pintail feathers, one of them ex- 

 clusively. Another had dog hairs interspersed among the feathers. 

 One nest contained a soft mass of the thin, wiry mosses that carpet 

 the ground. The presence of a small patch of lemming fur in the 

 bottom of another suggests the birds sometimes raid this animal's old 

 winter nests that are found everywhere above the ground. One 

 enterprising bird that built near the railway station used shreds of 

 waste cloth. 



The average dimensions of tree sparrow nests at Churchill were as 

 follows: 



Exterior Interior 



diameter diameter Interior Depth 



{lop, in {top, in depth {in overall {in Weight 



millimeters) millimeters) millimeters) millimeters) {in grams) 



Nest building is by the female alone, but her mate takes an active 

 interest in her activities and is never far away. Singing a few feet 

 above her while she works at the nest, he frisks dutifully after her when 



