fox sparrow: northwestern coastal 1421 



leaves, moss, and weathered grasses, and the lining is of finely frayed- 

 out grasses mixed with duck feathers." He (1910) describes a nest 

 of sinuosa found on Montague Island as "composed externally of a 

 mixture of green moss, skeletonized leaves and coarse grasses, while 

 in strong contrast there is internally a thick lining of fine, round grass 

 stems." 



Swarth (1912b) found fuliginosa on Vancouver Island on bush- 

 covered slopes and in willow thickets along the creek bottoms, but 

 not in the dense forests below. "They were very shy, and clung to 

 the thickets of dense underbrush, so that is was difficult to get sight 

 of one. Singing birds were usually perched on a projecting branch, 

 about the center of an impenetrable thicket of salmonberry or alder 

 into which they plunged at the first intimation of danger." 



The migration of this group of buds has interesting aspects. As 

 Swarth (1920) points out, they " * * * move directly southward 

 along the Pacific coast, each [subspecies] into a more or less definitely 

 circumscribed winter habitat. * * * The subspecies breeding at the 

 northern extreme, unalaschcensis, insularis, and sinuosa, move the 

 farthest south in winter, passing completely over both summer and 

 winter habitats of annectens, toumsendi, and fuliginosa, and reaching 

 the extreme southern limits of California." 



In his review of Swarth's 1920 opus, Percy A. Taverner (1921) 

 comments: 



Another important point brought out is that the birds breeding in the most 

 humid climates are not the darkest or the largest of the species. Unalaschcensis, 

 summering in the extremely moist Alaskan Peninsula, does not reach the extreme 

 development of size or depth of color that is attained by fuliginosa, resident on 

 the comparatively dry Vancouver Island region. This perplexing fact that would 

 otherwise seriously shake one of our most cherished ecological principles * is 

 explained by the fact that the northern race spends its winter in arid southern 

 California, and probably experiences a much lower annual average moisture than 

 does the darker and larger race. It is thus brought forcibly to our notice that, in 

 studying the relationship between the bird and its environment, winter ranges 

 and probably migrational routes should also be taken into consideration. 



Grinnell and Miller (1944) describe the winter habitats of these 

 subspecies in California as follows: 



P. i. unalaschcensis: Chaparral, principally of "hard" or arid type. The ground 

 litter beneath the screening cover of the chaparral plants is searched over and 

 scratched through in foraging in a fashion typical of all winter visitant races of 

 Fox Sparrows. 



P. i. insularis: Chaparral areas, but apparently on the average of somewhat 

 less arid type than those frequented by the races P. i. altivagans and P. i. un- 

 alaschcensis. 



*Gloger's Rule, that dark pigments increase with environmental humidity. 



