A History of North American Birds, Land Birds. Volume 3. Robert Ridgway
subsequent notes, Mr. MacFarlane repeats his observations that this species constructs no nest, merely laying its eggs on a ledge of shale or other rock. Both parents were invariably seen about the spot. In some instances the eggs found were much larger than in others.
Mr. Dall mentions shooting a pair near Nuk´koh, on the Yukon River, that had a nest on a dead spruce. The young, on the 1st of June, were nearly ready to fly. It was not a common species, but was found from Nulato to Sitka and Kodiak.
In regard to general characteristics of this Falcon, they do not apparently differ in any essential respects from those of the better-known Falco communis of the Old World. It flies with immense rapidity, rarely sails in the manner of other Hawks, and then only for brief periods and when disappointed in some attempt upon its prey. In such cases, Mr. Audubon states, it merely rises in a broad spiral circuit, in order to reconnoitre a space below. It then flies swiftly off in quest of plunder. These flights are made in the manner of the Wild Pigeon. When it perceives its object, it increases the flappings of its wings, and pursues its victim with a surprising rapidity. It turns, and winds, and follows every change of motion of the object of pursuit with instantaneous quickness. Occasionally it seizes a bird too heavy to be managed, and if this be over the water it drops it, if the distance to land be too great, and flies off in pursuit of another. Mr. Audubon has known one of this species to come at the report of a gun, and carry off a Teal not thirty steps distant from the sportsman who had killed it. This daring conduct is a characteristic trait.
This bird is noted for its predatory attacks upon water-fowl, but it does not confine itself to such prey. In the interior, Richardson states that it preys upon the Wild Pigeon, and upon smaller birds. In one instance Audubon has known one to follow a tame Pigeon to its house, entering it at one hole and instantly flying out at the other. The same writer states that he has seen this bird feeding on dead fish that had floated to the banks of the Mississippi. Occasionally it alights on the dead branch of a tree in the neighborhood of marshy ground, and watches, apparently surveying, piece by piece, every portion of the territory. As soon as it perceives a suitable victim, it darts upon it like an arrow. While feeding, it is said to be very cleanly, tearing the flesh, after removing the feathers, into small pieces, and swallowing them one by one.
The European species, as is well known, was once largely trained for the chase, and even to this day is occasionally used for this purpose; its docility in confinement, and its wonderful powers of flight, rendering it an efficient assistant to the huntsman. We have no reason to doubt that our own bird might be made equally serviceable.
Excepting during the breeding-season, it is a solitary bird. It mates early in February, and even earlier in the winter. Early in the fall the families separate, and each bird seems to keep to itself until the period of reproduction returns.
In confinement, birds of this family become quite tame, can be trained to habits of wonderful docility and obedience, and evince even an affection for the one who cares for their wants.
This species appears to nest almost exclusively on cliffs, and rarely, if ever, to make any nests in other situations. In a few rare and exceptional cases this Falcon has been known to construct a nest in trees. Mr. Ord speaks of its thus nesting among the cedar swamps of New Jersey; but this fact has been discredited, and there has been no recent evidence of its thus breeding in that State. Mr. Dall found its nest in a tree in Alaska, but makes no mention of its peculiarities.
The eggs of this species are of a rounded-oval shape, and range from 2.00 to 2.22 inches in length, and from 1.60 to 1.90 in width. Five eggs, from Anderson River, have an average size of 2.09 by 1.65 inches. An egg from Mount Tom, Mass., is larger than any other I have seen, measuring 2.22 inches in length by 1.70 in breadth, and differs in the brighter coloring and a larger proportion of red in its markings. The ground is a deep cream-color, but is rarely visible, being generally so entirely overlaid by markings as nowhere to appear. In many the ground-color appears to have a reddish tinge, probably due to the brown markings which so nearly conceal it. In others, nothing appears but a deep coating of dark ferruginous or chocolate-brown, not homogeneous, but of varying depth of coloring, and here and there deepening into almost blackness. In one egg, from Anderson River, the cream-colored ground is very apparent, and only sparingly marked with blotches of a light brown, with a shading of bronze. An egg from the cabinet of Mr. Dickinson, of Springfield, taken on Mount Tom, Massachusetts, is boldly blotched with markings of a bright chestnut-brown, varying greatly in its shadings.
Æsalon, Kaup, 1829. (Type, Falco æsalon, Gmelin, = F. lithofalco, Gm.)
Hypotriorchis, Auct. nec Boie, 1826, the type of which is Falco subbuteo, Linn.
Dendrofalco, Gray, 1840. (Type, F. æsalon, Gmel.)
This subgenus contains, apparently, but the single species F. lithofalco, which is found nearly throughout the Northern Hemisphere, and in different climatic regions is modified into geographical races. Of these, North America possesses three, and Europe one; they may be distinguished as follows:—
F. lithofalco. Second and third quills longest; first usually shorter than, occasionally equal to, or rarely longer than, the fourth. Adult female, and young of both sexes. Above brownish, varying from pale earth-brown, or umber, to nearly black, plain, or with obscure transverse spotting of lighter; tail with five to eight lighter bands, which, however, are sometimes obsolete, except the terminal one. Beneath ochraceous-white, longitudinally striped with brown or dusky over the whole surface. Adult male (except in var. suckleyi and richardsoni?). Above plumbeous-blue, with darker shaft-streaks; tail with more or less distinct bands of black, and paler tip. Beneath much as in the female and young, but stripes usually narrower and more reddish. Wing, 7.20–9.00; tail, 4.90–6.30; culmen, .45–.60; tarsus, 1.30–1.60; middle toe, 1.15–1.51.
a. Adult male plumbeous-blue above; sexes very unlike in adult dress. Female and young without transverse spotting on upper parts.
Adult male. Tail deep plumbeous, tipped with ash, with six transverse series of dusky spots (which do not touch the shaft nor edge of the feathers) anterior to the subterminal zone, the black of which extends forward along the edge of the feather. Inner web of the longest primary with ten transverse spots of white. Streaks on the cheeks enlarged and blended, forming a conspicuous “mustache.” Pectoral markings linear black. The ochraceous wash deepest across the nape and breast, and along the sides, and very pale on the tibiæ. Adult female. Above brownish-plumbeous, the feathers becoming paler toward their margins, and with conspicuous black shaft-streaks. Tail with eight (three concealed) narrow bands of pale fulvous-ashy; longest primary with ten light spots on inner web. Outer webs of primaries with a few spots of ochraceous. Young. Similar to the ♀ adult, but with a more rusty cast to the plumage, and with more or less distinct transverse spots of paler on the upper parts. Wing, 7.60–9.00; tail, 5.10–6.30; culmen, .45–.55; tarsus, 1.35–1.47; middle toe, 1.15–1.35. Hab. Europe … var. lithofalco.58
Adult male. Tail light ash, tipped with white, and crossed by three or four nearly continuous narrow bands of black (extending over both webs, and crossing the shaft), anterior to the broad subterminal zone, the black of which does not run forward along the edge of the feathers. Inner web of longest primary with seven to nine transverse spots of white. Streaks on the cheeks sparse and fine, not condensed into a “mustache.” Pectoral markings broad clear brown. Ochraceous wash weak across the nape and breast, and along sides, and very deep on the tibiæ. Adult female. Above plumbeous-umber, without rusty margins to the feathers, and without conspicuous black shaft-streaks. Tail with only five (one concealed) narrow bands of pale ochraceous; outer webs of primaries without ochraceous spots; inner web of outer primary with eight spots of white. Young. Like the adult female, but darker. Wing, 7.90–8.25; tail, 5.15–5.25; tarsus, 1.00; middle toe, 1.25. Hab. Entire continent of North America; West Indies … var. columbarius.
b. Adult male not bluish? sexes similar? upper parts with lighter transverse spots.
Adult. Above light grayish-umber, or earth-brown, with more or less
Hab. Europe and Western Asia; Iceland.