Part 51

Rostrhamus sociabilis, var. plumbeus, RIDGWAY.

HOOK-BILL KITE; EVERGLADE KITE.

Rostrhamus sociabilis, VIEILL. D’ORB. Hist. Nat. Cuba, av. p. 15.—CASS. Birds N. Am. 1858, 38.—MAYNARD, Birds Florida, Prospectus, 1872.

SP. CHAR. Adult male (No. 61,187, Everglades, Florida; C. J. Maynard). Prevailing color plumbeous, becoming black on the secondaries, primaries, and tail, somewhat brownish-ashy on the wing-coverts, and with a glaucous cast on the neck, the head becoming nearly black anteriorly. Tail-coverts (the longer of the upper and all of the lower) and base of the tail pure white, this occupying more than the basal half of the outer feather, and changing into grayish-brown next the black; tail with a terminal band of grayish-brown, about .75 wide. Inner webs of primaries marbled, anterior to their emargination, with grayish and white. Tibiæ tinged with rusty fulvous. Wing-formula, 4, 3, 5–2–6–7, 1. Wing, 14.01; tail, 7.25; culmen, .95; tarsus, 1.90; middle toe, 1.55; hind claw, 1.10, the toe, .90. Bill deep black; cere and naked lore bright orange-red; feet deep orange-red.

Young female (Cuba; Dr. Gundlach, Coll. G. N. Lawrence). Prevailing color above brownish-black, with a glaucous cast on the dorsal region; tail deep black, with a faint greenish-bronze reflection, with white and grayish base and tip, as in the adult. Each feather of the upper parts rather broadly tipped with ochraceous-rufous; crown, occiput, and auriculars streaked longitudinally with the same. Prevailing color of the head and lower parts deep ochraceous, on the head forming a broad superciliary stripe from the forehead back to the occiput; throat and cheeks streaked longitudinally with dusky; crissum immaculate; other lower parts, including lining of the wing, thickly covered with large transverse spots of brownish-black. Upper tail-coverts white, with a blackish shaft-line; tail with the basal third white anteriorly and brownish-ashy next the black, and with a terminal band, about 1.00 wide, of brownish-ashy, passing into white at the tip. Under surface of primaries cream-color anterior to the emargination, towards the ends grayish, with transverse spots of dusky. Wing-formula, 4, 3=5–2–6–7, 1. Wing, 13.90; tail, 8.25; tarsus, 1.90; middle toe, 1.55.

An older specimen in young plumage (11,755, Florida) differs as follows: The colors generally are lighter, the ochraceous being more prevalent and lighter in tint; the throat is immaculate, and the markings beneath more longitudinal. The secondaries and primaries are broadly tipped with ochraceous. Wing, 14.00; tail, 7.20; tarsus, 1.95; middle toe, 1.50.

HAB. West Indies and Southern Florida.

LIST OF SPECIMENS EXAMINED.

National Museum, 3; Coll. C. J. Maynard, 7; Philadelphia Academy, 2; Museum Comp. Zoöl., 3; Coll. R. Ridgway, 1. Total, 16.

HABITS. The Black Kite is a Central and South American species, well known in that section, but having no other claim to be regarded as a bird of North America than its presence in a restricted portion of Florida, where it is, in the extreme southern section, not very uncommon, and where it is also known to breed. It was first taken in that peninsula by Mr. Edward Harris, and subsequently by Dr. Heermann. It was supposed by Mr. Harris to breed in Florida, from his meeting with young birds; and this supposition has been confirmed by Mr. Maynard, who has since found them nesting, and procured their eggs.

Mr. Salvin met with what he presumed to be this species in Central America, ascribing the immense flights of Hawks seen by him in the month of March, in the Pacific Coast region, migrating in a northwesterly direction, to this Kite. The bird was well known to the Spaniards under the name of Asacuani,—a term that has become proverbial for a person who is constantly wandering from place to place. Mr. Leyland obtained a single specimen of the Rostrhamus near the Lake of Peten. In the spring of 1870, Mr. Maynard met with several individuals of this species among the Florida everglades. He first observed one on February 18, but was not able to secure it. Visiting the same spot ten days later, with Mr. Henshaw, three birds of this species were shot, and the nest of one was discovered. It was at that time only partly completed, was small, flat, and composed of sticks somewhat carelessly arranged. It was built upon the top of some tall saw-grass, by which it was supported. This grass was so luxuriant and thick that it bore Mr. Maynard up as he sought to reach the nest, which did not contain any eggs. On the 24th of March, Mr. Maynard discovered another nest of this species. It was built in a bush of the Magnolia glauca, and was about four feet from the water. It contained one egg. It was about one foot in diameter, was quite flat, and was composed of sticks carelessly arranged, and lined with a few dry heads of the saw-grass. The female was shot, and found to contain an egg nearly ready for exclusion, but as yet unspotted. Other eggs were subsequently procured through the aid of Seminole Indians, by whom this Hawk is called So-for-funi-kar.

The usual number of eggs laid by this Kite is supposed to be two, as in three instances no more were found, and this was said to be their complement by the Indians. It also appeared to be somewhat irregular in the time of depositing its eggs.

This Hawk is described as very sociable in its habits, unlike, in this respect, most other birds of prey. Six or eight specimens were frequently seen flying together, at one time, over the marshes, or sitting in company on the same bush. In their flight they resemble the common Marsh Hawk, are very unsuspicious, and may be quite readily approached. The dissection of the specimens showed that this bird feeds largely on a species of freshwater shell (Pomus depressa of Say).

The egg of this species taken in Florida by Mr. Maynard is of a rounded oval shape, equally obtuse at either end, and measures 1.70 inches in length by 1.45 in breadth. The ground-color is a dingy white, irregularly, and in some parts profusely, blotched with groups of markings of a yellowish brown, shading from a light olive-brown to a much duller color, almost to a black hue. These markings in the specimen seen are not grouped around either end, but form a confluent belt around the central portions of the egg. The following description is given by Mr. Maynard of the other specimens taken by him.

Egg No. 1. Ground-color bluish-white, spotted and blotched everywhere with brown and umber. Dimensions, 1.72 × 1.45. No. 2. Ground-color same as No. 1. Two large irregular blotches of dark brown and umber on the larger end, with smaller confluent blotches and streaks of the same, covering nearly the entire surface of that end; smaller end much more sparsely spotted with the same. Dimensions, 1.76 × 1.40. No. 3. Ground-color dirty brown. The entire egg, except the small end, covered with a washing of dark brown, which forms dark irregular blotches at various points, as if the egg had been painted and then taken in the fingers before drying. Dimensions, 1.55 × 1.55.

GENUS CIRCUS, LACEPEDE.

Circus, LACÉP. 1800, 1801. (Type, Falco æruginosus, LINN.) Pygargus, KOCH, 1816. (Same type.) Strigiceps, BONAP. 1831. (Type, Falco cyaneus, LINN.) Glaucopteryx, KAUP, 1844. (Type, Falco cineraceus, MONT.) Spilocircus, KAUP, 1847. (Type, Circus jardini, GOULD.) Pterocircus, KAUP, 1851. (Same type.) Spizacircus and Spiziacircus, KAUP, 1844 and 1851. (Type, Circus macropterus, VIEILL.)

=1042=, ♀. ½ ½ ¼

Circus hudsonius.]

GEN. CHAR. Form very slender, the wings and tail very long, the head small, bill weak, and feet slender. Face surrounded by a ruff of stiff, compact feathers, as in the Owls (nearly obsolete in some species). Bill weak, much compressed; the upper outline of the cere greatly ascending basally, and arched posteriorly, the commissure with a faint lobe; nostril oval, horizontal. Loral bristles fine and elongated, curving upwards, their ends reaching above the top of the cere. Superciliary shield small, but prominent. Tarsus more than twice the middle toe, slender, and with perfect frontal and posterior continuous series of regular transverse scutellæ; toes slender, the outer longer than the inner; claws strongly curved, very acute. Wings very long, the third or fourth quills longest; first shorter than the sixth; outer three to five with inner webs sinuated. Tail very long, about two thirds the wing; rounded.

The relationships of this well-marked genus are, to Accipiter on the one hand, and Elanus on the other; nearest the former, though it is not very intimately allied to either. I cannot admit the subgenera proposed by various authors (see synonomy above), as I consider the characters upon which they are based to be merely of specific importance, scarcely two species being exactly alike in the minute details of their form.

The species are quite numerous, numbering about twenty, of which only about four (including the climatic sub-species, or geographical races) are American. North America possesses but one (C. hudsonius, Linn.), and this, with the C. cinereus, Vieill., of South America, I consider to be a geographical race of C. cyaneus of Europe.

The birds of this genus frequent open, generally marshy, localities, where they course over the meadows, moors, or marshes, with a steady, gliding flight, seldom flapping, in pursuit of their food, which consists mainly of mice, small birds, and reptiles. Their assault upon the latter is sudden and determined, like the “Swift Hawks,” or the species of Accipiter.

In the following synopsis, I include only the three forms of C. cyaneus, giving the characters of the European race along with those of the two American ones.

Species and Races.

=C. cyaneus.= Wing, 12.50–16.00; tail, 9.00–10.70; culmen, .60–.80; tarsus, 2.42–3.25; middle toe, 1.10–1.55. Third to fourth quills longest; first shorter than sixth or seventh; outer four with inner webs sinuated. Adult male. Above pearly-ash, with a bluish cast in some parts; breast similar; beneath white, with or without rufous markings. Adult female. Above brown, variegated with ochraceous on the scapulars and wing-coverts; beneath yellowish-white or pale ochraceous, with a few longitudinal stripes of brown. Young (of both sexes). Like the adult female, but darker brown above, the spotting deeper ochraceous, or rufous; beneath pale rufous, the stripes less distinct.

Tail and secondaries without a subterminal band of dusky; lower parts without any markings.

Wing, 12.50–15.00; tail, 9.00–10.70; culmen, .60–.75; tarsus, 2.70–2.85; middle toe, 1.10–1.35. Hab. Europe …