COASTAL SAVANNAH SPARROW 713 



mental requisite (J. T. Marshall, Jr., 1948), and their ecologic distri- 

 butions probably reflect the habitat preferences of the two species. 



Breeding. — In early spring when the territorial males have appor- 

 tioned the available suitable area, it is possible to walk out on the 

 vast, damp stilicornia flats and see them perched on their song-posts, 

 usually no more than a foot higher than surrounding vegetation, 

 singing their thin abstraction of an emberizine song: sic-sic-sic-seeee, 

 seer. As notes of very high frequency are dominant components, in 

 a wind the listener usuaUy misses part of the song. The males flush 

 while the intruder is yet 30 to 40 yards away and move to the farthest 

 corner of the area with which they are familiar. Females seemingly 

 avoid human observation by running along the mud away from the 

 intruder (see Foraging behavior). 



The breeding season around San Francisco Bay extends from 

 February to June. Males with testes enlarged to sizes typical of 

 breeding males have been taken in mid-February on San Pablo salt 

 marsh. Contra Costa County. Eggs are laid between March 12 and 

 June 15 (sample of 61 records) with the peak of egg-laying (22 clutches) 

 occurring between April 1 and April 10. The species is probably 

 double-brooded, but the data at hand curiously indicate only one. 

 clear-cut peak to egg-lajdng. 



Nests, apparently constructed by females alone, are tightly 

 formed, relatively deep cups composed of dead stems of a variety of 

 grasses, salicornia stalks, and hairs; around Humboldt Bay, eelgrass 

 (Zostera) is occasional!}^ used (Robert Talmadge, in litt.). Nests 

 are placed most frequently in salicornia, less so in saltgrass {Dis- 

 tichlis spicata) or in upland grasses on the high parts of marshes. 

 Position of nests is low: of 1 1 nests in one sample, 8 were on the ground 

 surface, 1 was one inch high, 1 three inches, and 1 fom* inches; this is 

 to be contrasted vdth the statement of J. GrinneU and S. H. Miller 

 (1944) that nests are "usually slightly above the mud." 



Nests are well-concealed by overhanging vegetation. The in- 

 cubating and brooding birds are exceedingly tight sitters and do not 

 flush until an intruder steps almost upon the nests. At flushing, 

 most individuals give a distraction display (Johnston, 1957) consisting 

 of flight with shallow wingbeats, barely skimming the tops of the 

 salicornia stalks. The displaying individuals usually soon alight, per- 

 haps 30 yards away, and give thin, high-pitched alarm notes. 



Eggs. — Clutch size is 4.02 ±0.08 eggs (range 3 to 5; 50 records) 

 around San Francisco Bay. Clutches deposited in March average 

 3.50 eggs and the remainder average 4.09 eggs. The incubation 

 period in one nest was 12}^ days, last egg laid to last egg hatched. 

 The young are typically altricial and the natal down is sparse. 



