Length to end of tail 5 9/12 inches; wing from flexure 3 8/12; tail 2.
ICELAND OR JER FALCON.
Falco islandicus, Lath.
PLATE CCCLXVI. Adult Female.
The figures of the adult female of this superb Falcon now before you were taken from the bird described by Mr John Heppenstall, at page 554 of the second volume of this work. It was kept by him upwards of six years; and it was his intention to have sent it to me alive from Sheffield; but it died of an affection of the œsophagus, which had for some days rendered it unable to swallow its food. My kind and most worthy friend, however, sent it to me immediately, so that after having received it in good condition, I was enabled not only to make it the subject of the present plate, and to take accurate measurements of all its parts, but also to institute a comparison between it and one of the specimens obtained in Labrador, which, with its consort, is represented in Plate CXCVI.
In all essential respects it agrees with the Labrador bird. The festoon on the edge of the lower mandible is however more prominent, and on the other hand, the tooth which is prominent in the young bird from Labrador, is in the old Iceland bird broken off and worn on both sides. In like manner, several of the claws, which are larger and stronger in this individual, are worn and blunted. These are the accidents of domestication or long use, and shew that no dependence can be placed on the prominence of either the festoon or the tooth of the bill as indicating a difference of species. The tarsi, toes, their scales and scutella, are the same as in the Labrador specimen. The wing, however, is more pointed, although the feathers are of the same form; but this arises from the first quill of the Labrador bird not having completed its growth, as both it and some of the other quills are still sheathed at the base. In Mr Heppenstall’s bird the second quill is longest, the third very little shorter, and the first nearly as long, and three quarters of an inch longer than the fourth. The tail is slightly rounded, as in the Labrador bird, the lateral feathers being three quarters of an inch shorter than the longest, and the feathers are similarly though less distinctly pointed, they having been considerably worn. The plumage is compact, and the feathers are of the same form in both birds, but those of the head are a little broader in the Iceland bird. On the whole, however, no differences are observable beyond what might be expected between a young and an old individual of the same species. The colouring of the Iceland bird, however, is very different.
The bill is very pale blue, the extremity of the upper mandible black, that of the lower yellowish; the eyes greyish-black; the cere, superciliary ridge, edges of eyelids, tarsi and toes, pale yellow; the eyelids pale blue; the claws black. The plumage is pure white, but all the feathers of the back and rump, the scapulars, the wing-coverts, and the secondary quills, have near their extremity a brownish-black spot, generally arrow-shaped. The anterior feathers of the back have, moreover, a black streak on the shaft, which on those farther back becomes larger and lanceolate, and on the rump is accompanied by a third spot; the larger coverts and secondary quills have also three or more spots, and the primary quills have seven spots or partial bars toward their extremity, besides a large subterminal black space, their tips however being white. On the inner margin of the two middle tail-feathers are eight, and on the outer four dusky spots, and their shafts are also dusky, as are those of all the quills on their upper surface. There are also a few slight lanceolate dark spots on the sides of the body, and on the tibial feathers.
Length to end of tail 23 1/2 inches, to end of wings 21 1/2, to end of claws 18 3/4, to carpal joint 5 1/2; extent of wings 51 1/4; breadth of gape 1 1/8; wing from flexure 17; tail 9 3/4; bill along the ridge 1 5/12; tarsus 2 4/12; hind toe 1 1/12, its claw 1 5/12; middle toe 2 1/12, its claw (worn) 11/12. Weight 2 lb., it being much emaciated.
The tongue, a, is 10 1/2 twelfths long, fleshy, deeply emarginate at the base, having on its upper surface numerous orifices of mucous crypts, towards the end narrowed, deeply concave, horny, with the extremity rounded and very slightly emarginate. The œsophagus, b c d e, is 7 1/2 inches long, wide, dilated into a large crop, c d, lying on the right side; the proventriculus, f, is 1/2 inch in diameter, with a belt of oblong glandules, arranged into four very prominent longitudinal ridges, with deep grooves between them. The stomach, f g h, is round, compressed, 1 1/2 inch in length, 1 inch 5 twelfths in breadth; its muscular coat thin, composed of large fasciculi, not arranged into distinct muscles; its inner coat soft, without horny epithelium, but irregularly rugous, especially towards the pylorus, which has three knobs or valves. The intestine, h i j k, is 36 1/2 inches long, 5 twelfths in diameter at its anterior part, gradually contracting to 4 twelfths. The rectum is 3 1/2 inches long, 1/2 inch in diameter at the commencement; the cœca 2 twelfths long, 1 1/2 twelfth in diameter; the cloaca, l m, globular. The right lobe of the liver is 2 inches 4 twelfths long, the left 2 inches 1 twelfth; the gall-bladder large.
The crop or dilatation of the œsophagus was nearly filled by two excrescences from its inner surface, of a soft spongy texture, but not ulcerated, or in any part scirrhous. The inner surface of the stomach was similarly affected, but in a much less degree, and the pyloric region was indurated. The intestines quite sound.
