Washington Birds 1: pp 22-23, 1989

PLUMAGES OF WASHINGTON'S RAIL CHICKS

Ian Paulsen
9501 Moran Road NE, Bainbridge Island, WA 98110

Plumages of Virginia Rail (Rallus limicola) and Soya (Porzana carolina) chicks were until recently poorly described. This has hampered their identification because of inaccurate portrayals in the few standard North American field guides that attempt to illustrate them. Even in Ripley (1977), the plumage descriptions are inaccurate and generally follow Bent (1926).

In a recent book describing the chicks of all North American birds, Harrison (1978:25) stated: "In illustrating downy young and nestlings the artist has, where direct information was not available, deduced probable colors from preserved material or from juvenile birds." Unfortunately, the plumages of Virginia Rail and Sora chicks at that time were still not correctly described, thus explaining the inaccuracies in his illustrations (Harrison 1978: Pl. 9). 

Kaufmann (1987) determined the plumage sequences after a six-year study of these two species in the field and in captivity, and I reiterate his findings herein, supplemented by my own encounters with chicks of both species. I observed Virginia Rail chicks on 25 June 1986, near Fay Bainbridge State Park, and Sora chicks on 30 May 1989 at Battle Point Park, both on Bainbridge Island, Kitsap County, Washington. An adult bird with the chicks provided positive identification on each occasion. Using Kaufmann's aging criteria, the chicks on both occasions were slightly less than one week old.

Both species' chicks are mostly covered with black down as illustrated in many field guides, although there are bare areas on the crown and around the eyes. These areas are not very noticeable in the field due to the dark pigmentation of the skin. The Sora chick has a tuft of orangeish down at the base of the lower mandible during the first week after hatching, but it disappears by the second. The most distinctive difference between chicks of the two species is in the bill color. The bill of a Virginia Rail chick is pale pink with a narrow band of black about midway down it; the entire bill turns black by the end of the first month. The Sora chick's bill is whitish with a blood-red eye. Because of this and the orangeish tuft, the overall appearance of the Sora chick is of a bird with a gaudy head, somewhat similar to an American Coot (Fulica americans) chick. In the second week of life the tip of the bill darkens and the cere shrinks and becomes duller in color. The base of the lower mandible turns a pale orange-yellow, the base of the upper mandible nearly white. In the third week the cere is nearly gone, and the base of the upper mandible is a rosy color.

Foot and leg color also differs between the two chicks. In the Virginia Rail the color is dark brownish black, remaining that way for about a month and then changing to dusky-brown. In the Sora the feet and legs are light pink during the first week and change through dull gray and gray- green to yellow-green by the end of four weeks. Thus the legs of Sora chicks are always paler than those of Virginia Rails. The molt into juvenile plumage (illustrated in field guides) begins at two and one-half weeks and continues for three to four weeks. Thanks to Kaufmann's research, the downy plumages of at least these two rail species have been well described. There is, however, much more work needed on downy plumages of many groups with precocial young, including rails.

LITERATURE CITED

Bent, A- C. 1926. Life Histories of North American Marsh Birds. U. S. Nat. Mus. Bull. 135. Harrison, C. 1978.

A Field Guide to the Nests, Eggs, and Nestlings of North American Birds. Collins, Glasgow.

Kaufmann, G. W. 1987. Growth and development of Sora and Virginia Rail chicks. Wilson Bull. 99: 432-440. 

Ripley, S. D. 1977. Rails of the World. David R. Godine, Boston.

Manuscript received 28 August 1989

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