96 



NORTH AMERICAN FAUNA 67 



to the recorded date. During the summer King Rails may restrict 

 their activities to a relatively small area for as long as 3 months, dur- 

 ing which time the adults are nesting and molting, and the young, 

 flightless for about 2 months after birth, are growing. 



The 4,000,000-acre Louisiana coastal marsh is the largest block of 

 breeding habitat in the range of the King Rail. The southern rice- 

 fields are a good example of an optimum breeding habitat. The breed- 

 ing density of a King Rail population in a South Carolina river marsh 

 was 25 males per 100 acres; in an inland Florida marsh the density 

 was 30 males per 100 acres. King and Clapper Rails were found breed- 

 ing in the same brackish marshes in Louisiana, Maryland, and 

 Delaware. 



King Rail sexes appear to be alike in plumage. The male averages 

 larger than the female. Immature birds apparently can be externally 

 distinguished from adults during the first autumn by the color of the 

 soft parts. Most rails in juvenal and first-winter (immature) plumage 

 have some white barring on the wing coverts. This is also true of some 

 adults. The light-phase adult plumage described by Ridgway and 

 Friedmann (1941) is probably typical of hybrids. The small sample 

 of weights and measurements given in this report indicates that the 

 King Rail averages slightly larger than the Clapper Rail. 



Molt is not well understood. Apparently all individuals molt after 

 the nesting season, but some also molt during it. 



King Rails are known to return to the same section of the same 

 marsh for several consecutive years to breed. Territories are estab- 

 lished and maintained by aggressive behavior, primarily that of the 

 male. The mating call, given by the male, presumably serves the same 

 purpose as the song of a passerine bird on its territory, namely to at- 

 tract a mate and to repel other birds of the same sex (but also, in the 

 case of the King Rail, to maintain contact after pairing) . 



The display of the male during prenuptial courtship consists mostly 

 in walking about with tail uplifted and white undertail coverts ex- 

 tended. After pairing, other forms of display and a repertoire of 

 subdued calls are used to maintain the pair bond. 



Copulation takes place near the nest site, before and during egg 

 laying. 



The nesting season of the King Rail is one of the longest among 

 birds in the South. In Florida, there is e\ddence of nesting from 

 J anuary to July ; and in Louisiana, from ^larch to September. In the 

 middle and northern latitudes the nesting season is usually about 3 

 to 4 months long. 



Since the Clapper Rail in South Carolina is known to be double- 

 brooded, it is possible that the King Rail in the southern part of its 

 range may also have more than one successful brood ; however, this 

 has not yet been established. 



