of optimal conditions. Sparrow populations are 

 closely related to the age of vegetation after fires. 

 Maximum density is achieved within 3 or 4 years 

 after a burn, followed by a sharp decline as the 

 dead component of vegetation increases. Pro- 

 longed absence of fire permits the elimination 

 of marsh by hardwood invasion. Colonies may be 

 enhanced or reduced by fire, depending on several 

 critical factors, such as burn pattern, percent of 

 contiguous habitat burned, size and percent of 

 colony evicted, proximity of and isolation from 

 adjacent colonies, and frequency and season of 

 burning (Werner 1975, 1976). 



The breeding season appears to be closely re- 

 lated to the hydroperiod of the marsh. Singing 

 and nesting decrease abruptly when when the on- 

 set of heavy rains causes the marsh to flood 

 (Werner 1979), MacKenzie 1977). Dew may be an 

 important source of moisture during the dry sea- 

 son (Werner 1975, 1976). 



Cape Sable sparrows interact very little with 

 other birds in their habitat area. Predation on 

 adult sparrows appears to be low. Mortality may 

 increase as summer floods inundate protective 

 vegetation. Nestlings are subject to attack by ants 

 (Werner 1975, 1976); 19% of nests surveyed by 

 Werner (1975) at Taylor Slough are known to 

 have failed due to predation. Similar failure of an 

 additional 6% is suspected. 



The entire nesting cycle is completed within 

 the confines of a male's territory. Werner (1975) 

 reported territories of from 0.3 to 6.8 ha, some of 

 them overlapping. Territories, generally retained 

 through successive breeding seasons, are defended 

 by song and occasional chasing and combat. Ave- 

 rage territory size decreased with increasing popu- 

 lation density following fire. New residents usual- 

 ly occupy suboptimal sites adjacent to established 

 occupants. 



POPULATION NUMBERS AND TRENDS 



Werner (1976) estimated the total Cape Sable 

 sparrow population at 1,900 to 2,800 birds. Over 

 95% live in 8,800 to 12,800 ha of marshland in 

 the Taylor Slough area of South Florida. Muhly 

 grass prairie provides the principal habitat. Werner 

 (1976) described this final stronghold as 'an area 

 of widely spaced individuals, broken by various 

 sized patches of unacceptable habitat, on which 

 islands of greater density appear and disappear, 

 following the tracks of fires. . . .' A formerly large 

 population adjoining Big Cypress Swamp (Stim- 

 son 1956) was devastated by extensive fires 

 during the spring breeding season (Stimson 1961, 



1968; Werner 1976, MacKenzie 1977). Recent 

 surveys indicate at least a 95% reduction since 

 1955. Only two singing males were recorded at 

 Ochopee site in 1975, compared with 10 in 1970 

 (Werner 1975, 1976, 1979). 



The species was regularly sighted on the coastal 

 marl prairie of Cape Sable between 1918 and 

 1935 (Howell 1919, 1932; Holt and Sutton 1926; 

 Nicholson 1928; Semple 1936; Stimson 1956). 

 Believed to have been extirpated by a severe hur- 

 ricane on 2 September 1935 (Stimson 1956, 

 1968), they were rediscovered on Cape Sable near 

 Little Fox Lake in 1970 (Werner 1971). Altera- 

 tion of the habitat by the storm of 1935 apparent- 

 ly is responsible for the population decline. Only 

 a few widely spaced individuals remain (Werner 

 1975, 1976). 



REPRODUCTION 



The potential breeding season slightly exceeds 

 5 months, extending from February to August. 

 Up to three broods are produced in a single sea- 

 son. The pair bond may change between broods 

 or continue over two consecutive years (Werner 

 1975, 1979). 



Normally, three or four eggs are laid per nest, 

 rarely two or five. Eggs are incubated by the fe- 

 male. Incubation requires more than 11 days. 

 Both parents feed the young. Flightless young 

 leave the nest 9 to 11 days after hatching; they 

 are capable of short flights about 2.5 weeks after 

 hatching (Werner 1976, 1979). They become 

 independent at about 45 days (MacKenzie 1977). 



Fledglings begin to molt in July; the post- 

 nuptial molt of adults is completed August to 

 September (Werner 1975). 



Photographs of nestlings appear in Werner 

 (1975). 



MANAGEMENT AND CONSERVATION 



Recovery efforts have emphasized determina- 

 tion of ecological requirements as well as restora- 

 tion and maintenance of habitat. Primary manage- 

 ment strategies involve controlling water, fire, and 

 exotics to maintain historic conditions. Acquisi- 

 tion and management of private land in Big Cy- 

 press area has been recommended (Werner 1979, 

 MacKenzie 1977). 



Specific management recommendations pro- 

 vided by Werner (1975) are: (1) eliminate exotic 

 plants and animals from areas occupied by Cape 

 Sable sparrows; (2) employ controlled periodic 

 burns to retard hardwood invasion of suitable 

 marshes; (3) restrict burning to August and Sep- 



