722 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 2 



PASSERCULUS SANDWICHENSIS ROSTRATUS (Cassin) 



Large-billed Savannah Sparrow 



Contributed by Wendell Taber 



Habits 



Until recently this well-marked race was considered a distinct species, 

 to which also were assigned the several other large-billed "marsh 

 sparrows" of coastal southern and Baja California and western Sonora. 

 The "rostratus" group, as these are still referred to within the sand- 

 wichensis complex, are characterized by a large gross bill with a culmen 

 outline varying from straight to strongly convex, and in addition by 

 a generally ill-defined and diffuse breast streaking. 



Nesting. — Bancroft (1927) states that rostratus nests in tall grass 

 subject to tidal overflow near the mouth of the Colorado River. He 

 says the nests are constructed of grass stems solely; they are not 

 lined and there is no thinning of grass stems toward the inside. 



Behavior. — J. Grinnell (1905) records rostratus as common in winter 

 in the salt marshes and along the beaches of Los Angeles County, 

 Calif., but less numerous than the race heldingi. In San Pedro harbor 

 rostratus frequents wharves and breakwaters and even hops fearlessly 

 about the decks of vessels, feeding on crumbs and flies. J. H. Bowles 

 (1911) attributes this behavior to spilled grain. 



A. W. Anthony (1906) states that the races rostratus and sanctorum 

 are equally abundant in September along the beaches of Los Benitos 

 Island, gleaning a livelihood from beds of stranded kelp, over which 

 the birds scurried like mice in search of insects and small marine hfe. 

 The Benito Islands offer no tidal flats or marsh lands. He also says 

 that the ocean beaches as far as Cape St. Lucas provide winter range 

 for rostratus. While the birds are by no means rare on both sandy 

 and rocky shores they are nowhere reaUy abundant away from the 

 tide flats of the bays. He had never seen rostratus over half a mile 

 from tide water and a bird that wanders over a few hundred yards 

 from the tide flats or beach is at once noticed as out of place. He 

 considered the race strictly littoral and states (1893) that he shot a 

 female rostratus at San Ramon in April 1887. He amplified this 

 statement (1906) pointing out that San Ramon was about 25 miles 

 north of San Quintin Bay on the coast of Lower California. The beach 

 was thickly covered by driftwood which reached back some 200 feet 

 to the sand dunes and was often piled up several feet high. Through 

 these tangled piles of drift rostratus were running, dodging in and out 

 very much after the manner of rock wrens in a pile of rocks. 



Plumages. — Van Rossem (1947) refers to the plumage coloration as 

 being varied "but usually with a definite pinkish or reddish tone 



