Habits. The common Bank Swallow as we know it, or Sand Martin as it is called in England, is nearly or quite cosmopolitan in its distribution. Found throughout Europe in the season of reproduction, and in portions of Africa in the winter months, it is equally common throughout North America in the summer, and probably winters in Mexico and in Central and South America, though it is not mentioned by Sumichrast as a bird of Vera Cruz. It is said to occur in various parts of the continent of Africa, and in Europe it extends its migrations to the extreme northern regions. It has also been met with in India and in Siberia. Mr. Salvin obtained several specimens at Duenas, Guatemala, in September, 1861, having previously observed it about the Lake of Yzabah.

On both continents it is somewhat local in its distribution, in favorable localities being quite abundant, and in others not known to exist. It is an early spring visitant wherever found, appearing in England by the 24th of March, and even in our high Arctic regions early in May, often in such inclement weather that it is obliged to take refuge in holes. Mr. Dall met with this species in Alaska, in favorable situations, in immense numbers. He counted on the face of one sand-bluff over seven hundred nest-holes made by these birds, and all of them apparently occupied, so that the bluff presented the appearance of an immense honeycomb alive with bees. He states that it takes the bird four days to excavate its nest. Rev. F. O. Morris, on the other hand, who has closely watched their operations in England, says that it requires a fortnight, and that the weight of sand a pair of these birds removes is twenty ounces in a day. Pebbles of more than two ounces in weight have been known to be taken out by them.

The flight of this species is rapid, but unsteady and flickering. In searching for their food they skim low over the surface of both land and water, dropping upon the latter, as they fly, to drink or to bathe. Their food consists of the smaller kinds of winged insects, which they pursue and capture, dashing at them at times even on the water. They usually feed their young with larger kinds than they eat themselves.

Mr. Augustus Fowler mentions a remarkable instance of sagacity and provident forethought in these birds, not easily separable from reason. In the town of Beverly, in a stratum of sandy loam, he observed each season a colony of some twenty or thirty pairs of these birds. In this place these birds never burrowed more than two or three feet. Within a mile of this place another colony excavated a bank in which the layer of loam was mixed with small stones. In this bank they excavated to the depth of five, seven, and even nine feet. Why was there this extraordinary difference in the length of burrows made by the same species, in situations not more than a mile apart? The reason for this difference, upon examination, became very obvious. We give the explanation in Mr. Fowler’s own words: “In one bank, where the earth was of a fine sandy loam, easily perforated, from the entrance to the extremity the burrows did not exceed three feet in length; while in the other bank, with harder loam to work in, one burrow was found nine feet in length. After examining six holes of nearly equal length, it appeared that these little birds had sufficient reason for extending their labors so far into the earth. In every instance, where they met with a spot free from stones they finished their burrows; thus showing great care for the welfare of their eggs or young by avoiding, in the stony soil, a catastrophe so great as would befall their treasures if by accident one of these stones should fall upon them.”

The work of perforation they perform with their closed bill, swaying the body round on the feet, beginning at the centre and working outwards. This long and often winding gallery gradually expands into a small spherical apartment, on the floor of which they form a rude nest of straw and feathers. The time occupied in making these excavations varies greatly with the nature of the soil, from four or five days to twice that number.

Their eggs are five in number, pure white, and when unblown have a fine roseate hue. They are oval in shape, larger at one end, and pointed at the smaller. Their average length is .72 of an inch, and their average breadth .47.

We now come to the consideration of three families of Oscine birds, of pre-eminently dentirostral type, having certain common characters by which they are distinguishable, with but little difficulty, from all others. In their close relationship it has been questioned by many whether they do not all belong under one head, but they are more generally considered distinct. The common characters, and those peculiar to each, are as follows:—

Common Characters. Bill stout, and considerably hooked at tip, or with the point bent abruptly downward; with a deep notch, and sometimes a tooth or lobe just behind the notch; the tip of the lower mandible likewise frequently bent up, and with a notch behind it. The nostrils lateral, the bristles of the mouth generally well developed. The primaries are ten (except in a few Vireos), the outer from one fourth to one half the second. Tail variable. Tarsi scutellate anteriorly; sometimes with a tendency to division on the lateral plates; hitherto not met with. Basal joints of toes more adherent. Separated from Turdidæ by greater adhesion of toes; from Troglodytidæ by notched and hooked bill, etc.

A. Basal phalanx of anterior toes abbreviated; that of median toe decidedly shorter than the basal of inner, or the two basal of outer, and adherent for its whole length on both sides to the lateral (i. e. not free at all). Lateral plates of tarsus undivided, except at extreme lower end.

Vireonidæ. Gonys more than half the length of lower jaw (from tip to angle of mouth), usually longer than width of mouth, which is narrow. Bill conical, much compressed, decurved at end and notched, but scarcely toothed. Frontal feathers bristly and erect, or bent but slightly forward. Nostrils overhung by membrane. Tarsus longer than middle toe and claw. Lateral toes generally unequal; outer claw reaching half-way along middle claw.

B. Basal phalanx of middle toe about as long as the basal of inner, or the two basal of outer; free externally, at least for about one third its length, internally for about one half. Lateral plates of tarsus with decided tendency to subdivision (except in Myiadestinæ).

Ampelidæ. Gonys decidedly less than half the length of lower jaw, or than width of mouth, which is very broad and deeply cleft. Bill triangular, much depressed, decurved at end and notched, with moderate though decided tooth. Frontal feathers rather soft, scarcely bristly or erect. Nostrils overhung by membrane. Tarsus equal to or shorter than middle toe and claw. Lateral toes nearly equal; outer claw reaching only to base of middle claw.

Laniidæ. Gonys about half the length of lower jaw; about equal to width of mouth. Bill very powerful and raptorial, much compressed, with a strongly marked hook, notch, and tooth at end. Frontal feathers very bristly, and directed forwards, so as to conceal nostrils and base of bill. Nostrils with bony walls, except behind. Tarsus longer than middle toe and claw, sometimes much scutellate on sides. Lateral claws nearly equal; outer claw reaching a little beyond base of middle claw.