This species was first found breeding in Carlisle, Penn., by Professor Baird, in the summer of 1843. The following year I visited this locality early in June, and had an opportunity to study its habits during its breeding-season. We found the bird rather common, and examined a number of their nests. None that we met with were in places that had been excavated by the birds, although the previous season several had been found that had apparently been excavated in banks in the same manner with the Bank Swallow. All the nests (seven in number) that we then met with were in situations accidentally adapted to their need, and all were directly over running water. Some were constructed in crevices between the stones in the walls and arches of bridges. In several instances the nests were but little above the surface of the stream. In one, the first laying had been flooded, and the eggs chilled. The birds had constructed another nest above the first one, in which were six fresh eggs, as many as in the other. One nest had been built between the stones of the wall that formed one of the sides of the flume of a mill. Two feet above it was a frequented footpath, and, at the same distance below, the water of the mill-stream. Another nest was between the boards of a small building in which revolved a water-wheel. The entrance to it was through a knot-hole in the outer partition, and the nest rested on a small rafter between the outer and the inner boardings.
The nests were similar in their construction to those of the Bank Swallow, composed of dry grasses, straws, and leaves, and lined with a few feathers; but a much greater amount of material was made use of, owing, perhaps, to the exposed positions in which they were built.
The eggs, six in number, in every instance that we noticed, were pure white, about the size of those of the riparia, but a little more uniformly oblong in shape and pointed at one end. Their length varies from .78 to .69 of an inch, the average being .75. Their average breadth is .53 of an inch.
Genus COTYLE, Boie.
Cotyle, Boie, Isis, 1822, 550. (Type, Hirundo riparia, L.)
Gen. Char. Bill small; nostrils lateral, overhung by a straight-edged membrane. Tarsus about equal to middle toe without claw; feathered at upper end, especially on inner face, and having also a small tuft of feathers attached to posterior edge near the hind toe. Middle toe with basal joint adherent externally to near the end, half-way internally, the claws comparatively little curved, the lateral reaching beyond the base of the middle. Tail slightly forked. Color dull lustreless brown above, in riparia white beneath with gray pectoral band. Nests in holes in banks; eggs white.
Cotyle riparia.
20641
Many American birds have been referred to Cotyle, but the only one really belonging to the genus is the cosmopolitan C. riparia. The peculiarity of the genus consists essentially in the tuft of tarsal feathers at the base of the hind toe, and the unusual length of the lateral claws, combined with the lateral nostrils overhung by membrane. By these characters the genus is very easily distinguished from Stelgidopteryx.
Cotyle riparia, Boie.