According to Audubon, the Marsh Hawk rarely pursues birds on the wing, nor does it often carry its prey to any distance before it alights and devours it. While engaged in feeding, it may be readily approached, surprised, and shot. When wounded, it endeavors to make off by long leaps; and when overtaken, it throws itself on the back and fights furiously. In winter its notes while on the wing are sharp, and are said to resemble the syllables _pee-pee-pee_. The love-notes are similar to those of the _columbarius_. Mr. Audubon has found this Hawk nesting not only in lowlands near the sea-shore, but also in the barrens of Kentucky and on the cleared table-lands of the Alleghanies, and once in the high covered pine-barrens of Florida. After having paired, the Marsh Hawks invariably keep together, and labor conjointly in the construction of the nest, in sitting upon the eggs, and in feeding the young. Their nests are variously constructed as to materials, usually chiefly of hay somewhat clumsily wrought together into the form of a nest, but never very nicely interwoven; occasionally, in more northern localities, they are lined with feathers, in some cases with pine-needles and small twigs. Richardson states that all the nests of this Hawk observed by him were built on the ground by the side of small lakes, of moss, grass, feathers, and hair, and contained from three to five eggs, of a bluish-white color, and unspotted. The latter measured 1.75 inches in length, and were an inch across where widest. The position and manner of constructing the nest correspond with my own experience, but the size of the eggs does not. The nests have been invariably on the ground, near water, built of dry grass, and lined with softer materials. Mr. Audubon gives a very minute account of a nest which he found on Galveston Island, Texas. It was about a hundred yards from a pond, on a ridge just raised above the marsh, and was made of dry grass; the internal diameter was eight, and the external twelve inches, with the depth of two and a half. No feathers were found. This absence of a warm lining in Texas really proves nothing. A warm lining may be required in latitude 65° north, and the same necessity not found in one of 29°. A nest observed in Concord, Mass., by Dr. H. R Storer, was on the edge of a pond, and was warmly lined with feathers and fine grasses. Many other instances might be named. The eggs found in the Galveston nest were four in number, smooth, considerably rounded or broadly elliptical, bluish-white, 1.75 inches in length, and 1.25 in breadth. Another nest, found under a low bush on the Alleghanies, was constructed in a similar manner, but was more bulky; the bed being four inches above the earth, and the egg slightly sprinkled with small marks of pale reddish-brown.