birds all favor the maintenance of the integrity and distinctness 

 of the population of song sparrows on the salt marsh. (B.W.) 



Keywords: sparrows, salt marshes, population structure, San Francisco Bay 



V-B-40 



Post, W, 1974. Functional analysis of space-related behavior in the 

 seaside sparrow. Ecology 55:564-575. 



This paper compares seaside sparrow ( Ammospiza maritima ) populations 

 nesting in two dispersion patterns: territories and grouped territories, 

 Territories, found in altered (ditched) salt marshes, were large, 

 all-purpose activity spaces. Grouped territories, found in unaltered 

 salt marshes, were small activity spaces from which birds made distant 

 foraging flights. 



Among the factors influencing the grouped territory spatial pattern, 

 the most important were nest site availability and lack of predation. 

 A scarcity of nest sites in the unaltered habitat appeared to require 

 the birds to nest close together, while such aggregation was made 

 possible by scarcity of ground predators. The territorial pattern 

 was thought to be influenced by low population density, low food avail- 

 ability, and sufficiency of nest sites. 



The amount of time that birds spent foraging, singing, and resting 

 did not differ between spatial patterns, nor did the diurnal pattern 

 of these activities. Birds on grouped territories spent more time 

 in aggression than did birds on territories. 



The breeding success of birds found in the two dispersion patterns 

 did not differ. The rate of delivery of food to the nest was also the 

 same, although birds on territories ilew twice as far to gather food 

 for their nests. 



The results suggest that both spatial patterns are equally successful 

 for the given conditions. Because of the variability of habitat, it is 

 doubtful that the space-related behavior of the seaside sparrow acts to 

 limit population size. (A. A.) 



Keywords: sparrows, salt marshes, behavior patterns 



235 



