572 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



"[it] occurs in cattail and tule marshes and in willow-cottonwood 

 association bordering valley streams." 



Nesting. — In his Birds of California, William Leon Dawson (1923) 

 writes : 



Nests of the yellow-throats are the commonplace of all swampy localities — 

 commonplace, yet never without interest, because of their varied architecture 

 and their diverse setting. A nest may be sunk firmly into a tussock of grass 

 barely clear of the ground or water, or it may be lashed firmly to stalks of an 

 investing clump of cattails, or it may be deftly hidden under a canopy of weed- 

 tops a hundred feet from water. The nest may be composed chiefly of brittle 

 weathered leaves or grass or sedge, so coherent as to be scarcely removeable, or 

 else it may be settled into a veritable fortress of coiled cattail leaves sturdy and 

 dependable. The lining too, may be of coiled grasses almost as light in color as 

 the speckled white eggs which they support, or it may be of black horsehair, 

 throwing the jewels into prized relief. 



Grinnell and Miller (1944) write: "nests are placed low down, often 

 over the water. Plant associations most likely to meet these require- 

 ments: growths of cattails, tules and other sedges, especially where 

 tangled and matted ; thickets of young willows ; blackberry vines, ac- 

 companied by nettles and dock." 



A nest collected at Fairbank, Ariz., is described by A. C. Bent (MS.) 

 as follows : "Bulky, loosely built nest made up entirely of coarse strips 

 of sacaton grass and other grasses; no plant down or other soft ma- 

 terial. The dimensions were, outer height 3 inches, diameter 41^ 

 inches, inner depth 2 inches and inner diameter 2y^ inches." 



W. L. Dawson (1923) states the nest is "of coui*se coiled grasses, or, 

 more rarely, leaves of Typha angustifolia; lined with fine grasses or 

 horse hair." Others have mentioned that a lining of horsehair is some- 

 times used, as is also the case of many nests built by the eastern forms 

 of the yellowthroat. 



Eggs. — The eggs vary from three to five in number but the majority 

 of the nests contain four eggs. They are similar in their markings 

 to those of other forms of yellowthroat, having a ground color of 

 white or creamy white, dotted and spotted or rarely streaked with 

 black, shades of brown, and lavender or vinaceous gray. The mark- 

 ings are usually concentrated about the larger end of the egg. 



Food. — F. E. L. Beal (1907) in an investigation of the food of the 

 western yellowthroat examined the contents of 114 stomachs of birds 

 taken in California during every month but January. He found the 

 yellowthroat to be practically wholly insectivorous and the insects 

 it eats to be either harmful or of little economic value. It eats no 

 fruit or grain, or, as far as known, any other useful product. Beal 

 states further : 



The animal matter amounted to 99.8 percent of the total food. The largest 

 item is Hymenoptera, amounting to 35 percent, of which about half is ants and 

 the remainder wild bees, wasps, etc. Hemlptera amount to 28 percent, and are 



