Young fully fledged. Plate CCCLVI. Fig. 3.
The young of both sexes when fully fledged, resemble the adult female, but have the colours of a richer or deeper tint; all the lower parts with an elongated brown streak on each feather; the upper tail-coverts white, with a lanceolate reddish-brown spot.
After the first moult, the male still resembles the adult female. At least, such is the case with a specimen presented to me by Dr Richardson, and marked “Buteo (Circus) cyaneus. Spec. N. 6. Male. May 31. 1826. Fort Franklin,” being the one elaborately described at p. 63 of the second volume of the Fauna Boreali-Americana. In this specimen the colours are much faded, and the feathers worn, the upper tail-coverts in particular being reduced almost to the shafts. It is valuable as indicating by two feathers on the leg, which are new, the next state of plumage of the male, which is as follows:—
The upper part of the head and the hind neck are light brownish-red, with dusky streaks, the white of the nuchal feathers conspicuous. The upper parts are brown, with a tinge of grey, more apparent on the wings, the scapulars and some of the smaller wing-coverts still marked as in the young and females; the upper tail-coverts pure white; the tail-feathers grey, with a tinge of brown, the lateral reddish-grey; the dark bars much diminished in breadth, and the inner webs still tinged with yellowish-red. The ruff is brownish-grey, margined with reddish-white; the fore part of the neck and breast pale brownish-red, tinged with grey, each feather marginally spotted or edged with dull white. The rest of the lower parts are white, the feathers generally with several spots of light red along the centre; these spots assuming the appearance of transverse bars on the sides and legs; the smaller wing coverts are similarly spotted, but those near the edge have only a dusky streak, and the secondary coverts are barred with dusky. The inner webs of the quills toward the base are white, with narrow bars of brownish-black, and the extremities of the primaries are as in the adult.
After a very careful comparison of seven skins of American birds with an equal number of European, no essential differences can be observed. I am therefore compelled to conclude, that the Marsh Hawk of America is the Hen-Harrier of Europe. The following measurements are obtained from a comparison of eight individuals.
| Amer. | Europ. | Amer. | Europ. | |||||||||||||
| M. | M. | M. | M. | F. | F. | F. | F. | |||||||||
| Length to end of tail, | 19 | 3/4 | 16 | 1/2 | 18 | 18 | 1/4 | 20 | 1/2 | 20 | 1/4 | 21 | 21 | |||
| ................................wings, | 16 | 1/2 | 14 | 1/2 | 15 | 3/4 | — | 18 | 3/4 | 18 | 1/2 | 18 | 1/2 | 19 | ||
| Extent of wings, | 44 | 40 | 1/2 | 40 | 39 | 1/2 | 46 | 3/8 | 45 | 1/2 | 46 | 46 | ||||
| Wing from flexure, | 14 | 4/12 | 13 | 13 | 1/2 | 13 | 15 | 1/4 | 14 | 9/12 | 14 | 1/4 | 15 | 1/4 | ||
| Tail, | 8 | 9/12 | 8 | 7/12 | 9 | 8 | 1/2 | 9 | 10/12 | 9 | 9/12 | 9 | 9/12 | 10 | ||
| Bill along the ridge, | 1 | 2/12 | 1 | 1 1/2/12 | 1 | 1/12 | 1 | 1/12 | 1 | 3/12 | 1 | 3/12 | 1 | 2/12 | 1 | 3/12 |
| Tarsus, | 2 | 8/12 | 2 | 9/12 | 2 | 1/2 | 2 | 8/12 | 3 | 2/12 | 3 | 2/12 | 2 | 9/12 | 2 | 9/12 |
| Hind toe, | 7 1/2/12 | 7 1/2/12 | 8/12 | 7/12 | 10/12 | 7 1/2/12 | 7 1/2/12 | 9/12 | ||||||||
| Its claw, | 10/12 | 10 1/2/12 | 9/12 | 9 1/2/12 | 1 | 2/12 | 1 | 1 | 1/12 | 11/12 | ||||||
| Middle toe, | 1 | 2 1/2/12 | 1 | 2 1/2/12 | 1 | 1/2 | 1 | 2/12 | 1 | 1/2 | 1 | 4/12 | 1 | 4/12 | 1 | 5/12 |
| Its claw, | 8 1/2/12 | 8 1/2/12 | 8/12 | 8 1/2/12 | 10/12 | 9 1/2/12 | 10/12 | 11/12 | ||||||||
| Anterior tarsal scutella, | 17 | 18 | 18 | 15 | 19 | 17 | 18 | — | ||||||||
| Scutella on first toe, | 7 | 6 | 6 | 6 | 7 | 5 | 6 | — | ||||||||
| second, | 5 | 5 | 5 | 5 | 5 | 5 | 5 | — | ||||||||
| third, | 16 | 17 | 18 | 15 | 16 | 16 | 17 | — | ||||||||
| fourth, | 7 | 8 | 7 | 7 | 8 | 7 | 8 | — | ||||||||
If measurements of this kind are calculated to throw light on the subject, the collectors of skins are welcome to the above, which have been made with as much accuracy as possible.
An adult male examined. On the roof of the mouth are two lateral and a median prominent ridge, the intervening space covered with small papillæ. The posterior aperture of the nares is oblong, 4 twelfths of an inch in length, but with an anterior slit 7 1/2 twelfths long. The tongue, a, is 8 1/2 twelfths long, fleshy, emarginate and papillate at the base, concave above, rounded and slightly emarginate at the tip. The mouth is 1 inch in breadth. The œsophagus, a b c d e, which is 6 inches long, is very wide, with very thin parietes, and on the lower part of the neck is dilated into a sac or crop, b c, which on being distended has a diameter of 2 inches at the widest part. It then contracts to 10 twelfths as it enters the thorax; its proventricular portion, d e, has a diameter of 1 inch. The stomach, e f g is roundish, 1 1/2 inch in diameter, somewhat compressed; its muscular coat extremely thin, being reduced to small parallel fasciculi converging toward two tendinous spaces of an elliptical form, and about half an inch long. The intestine, g h, is 3 feet 2 inches long; its diameter at the upper part 3 twelfths, towards the cœca 2 twelfths. The rectum, i j, is 2 inches long, not including the cloaca, j, which is globular and 1 inch in diameter. The cœca are extremely small, being 2 1/4 twelfths long, and 1 twelfth in diameter. The pylorus has no valve properly so called, but two ridges run from it into the intestine to the length of about 3 twelfths of an inch. The gall-bladder is 7 twelfths long and 4 twelfths in breadth.
In a very small male, the œsophagus is 4 3/4 inches long; the intestine 3 feet 4 inches. In a female, the intestine is 3 feet 9 inches long.