44 



NORTH AMERICAN FAUNA 67 



occurs. My recent investigations indicate that the so-called light phase 

 plumage is probably the result of hybridization or intergradation in 

 areas of mixed King and Clapper Rail populations, or it may be due 

 simply to individual variation. 



In my collection I have a series of 16 King and Clapper Rail speci- 

 mens taken from a 1 -square-mile area of brackish marsh in Delaware 

 (table 1). In this series there are Kings and Clappers with typical 

 plumages and also gradations from one type to the other. Some of 

 the specimens appear to be light phase King Rails. Ridgeway land 

 Friedmann (1941) made no mention of locality, habitat, or the possi- 

 bility of mixed populations where so-called light-phased birds were 

 collected. 



Table 6. — Weights of King and Clapper Rails 

 [In grains. All specimens were adults. Bottom line shows mean weights.] 



King Rail 



King Rail 



Clapper Rail 



Clapper Rail 



{R. e. elegansY 



{R. e. tenuirostris)^ 



(R.l. crepitans)^ 





(R.l.)^ 



Males 



Females 



Males Females 



Males Females 



Males 



Females 



339.9 



253.0 



271 220 



332.2 



300 



275 



366.0 



272.0 



306 255 



335.0 



325 



275 



367.9 



305.0 



317 268 





300 



275 



421.0 



313.3 



331 





325 



275 



427.0 



319.0 







300 



275 



436.0 



320.0 







350 



275 



438.3 



322.0 







300 



250 



453.0 



323. 0 







300 





490.0 



325.0 







325 













350 













350 













350 













325 





415.5 



305.9 



306. 3 247. 7 



333.6 



320.8 



271.4 



1 From Arkansas, Delaware, and Louisiana (author's data). 



2 All from Mexico (Warner and Dickerman, 1959, p. 50). 



3 Both from Delaware (author's data). 



* All from South CaroUna, each to nearest 25 grams; race {R. I. crepitans or R. I. waynei) not specified 

 (Blandin, 1963, p. 33). 



Table 7. — Measurements of King and Clapper Rails 



[From Ridgway and Friedmann, 1941. All specimens were adults. All measurements are given in mm. 

 Wing measurements are for the chord, from bend of wing to tip of longest primary] 



King Rail {R. e. elegans) Clapper Rail {R. I. aepitans) 



Males 1 Females 2 Males ^ Females * 



Range Average Range Average Range Average Range Average 



Wing 159. 0-177. 0 163. 4 147. 0-162. 0 154. 3 142. 5-159. 5 151. 1 135. 5-160. 0 146. 8 



Tail- 56.0- 72.5 65.9 60. 0- 70. 0 64.4 55.0- 69.0 64.6 55.0- 69.5 61.9 



Exposed 



culmen 58. 0- 65. 5 62. 5 50. 0- 63. 0 61. 9 55. 0- 69. 5 63. 3 53. 5- 67. 0 59. 6 



Tarsus 52. 0- 64. 0 58. 4 49. 5- 58. 0 54. 0 48. 0- 56. 0 51. 7 41. 0- 56. 0 48. 1 



Middle toe 



without 



claw 50. 5- 60. 5 55. 1 46. 0- 56. 0 50. 8 45. 5- 53. 5 48. 8 40. 0- 52. 0 45. 9 



1 18 specimens from Illinois, Missouri, District of Columbia, Virginia, Alabama, Louisiana, South Carolina, 

 and Florida. 



2 14 specimens from Illinois, District of Columbia, Maryland, Virginia, Louisiana, and Florida. 

 3 21 specimens from Massachusetts, New York, New Jersey, Virginia, and North Carolina. 

 * 17 specimens from New Jersey, Virginia, and North Carolina. 



Note.— An incubating female (adult ?) King Rail collected at Stuttgart, Ark., May 1962, had a left wing 

 measurement (chord) of only 141.0 mm.; a paired female (adult ?) collected at Taylor's Gut, Kent County, 

 Del., Apr. 15, 1963, had a left wing measurement (chord) of 145.0 mm. 



