46 



NORTH AMERICAN FAUNA 67 



meters greated than that for females. From late surmner to at least 

 early winter, the presence of a bursa in young birds will distinguish 

 them from adults. 



MOLTING 



Adult King Rails have a complete molt and are flightless for 

 nearly a month. Young of the year undergo a partial molt which does 

 not include the tail and flight feathers. 



In the Middle Atlantic States the molting season for King Rails 

 extends from the beginning of the breeding season in late May until 

 the beginning of fall migration in early October. 



In this study, breeding birds found in molt during May and June 

 were replacing only body feathers. Molt of the remiges and rectrices 

 was not observed until the first week in July. I have not been able to 

 ascertain the relation between the partial molt during the breeding 

 season and the complete molt in the summer. Birds that are renewing 

 their body feathers while nesting in May and June may be undergoing 

 prenuptial molts or early postnuptial molts during which the wing and 

 tail feathers are not dropped. 



Bent (1926, p. 262) stated that adult King Rails undergo a partial 

 molt of the contour plumage during early spring. Eight specimens 

 collected in the Middle Atlantic States in March and April showed no 

 signs of molt. An adult female King Rail in the U.S. National Mu- 

 seum, taken at Alligator Bluff, Kissimmee River, Fla., April 9, 1901, 

 was molting body feathers when collected. This could well have been 

 a breeding bird because in Florida this species begins nesting in late 

 winter. In my records the earliest recorded dates of molting by King 

 Rails are May 28, 1960, and May 29, 1964, when an adult or subadult 

 male and female, respectively, were found in breeding condition at 

 Woodland Beach, Del. The male had pinfeathers on the underside of 

 the neck, the sternal region, and the crural tract. Feather renewal on 

 the female appeared to be about three-fourths complete and was pro- 

 ceeding simultaneously in most areas of the body. Three King Rails in 

 breeding condition examined at Laurel, Md., June 12 and 18 and July 

 3, 1965, also were molting body feathers. 



Molting rails in breeding condition have previously been reported. 

 Watson (1962, p. 350) collected molting Spotted Rails {Pardirallus 

 maculatus) in breeding condition in Cuba; Warner and Dickerman 

 (1959, p. 50), working near Mexico City, reported two female King 

 Rails {Rallus elegans tenuirostris) molting in May during the nesting 

 season. 



My earliest example of a King Rail molting its wing and tail feathers 

 was at Laurel, Md., July 7, 1965. This bird was flightless. Two other 

 birds trapped at Laurel, one on July 14, 1967, the other on July 24, 

 1967, also were flightless. A female collected near Woodland Beach, 



