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THE ROUGH-LEGGED FALCON.
Fjlco lagopus, Gmel.
PLATE CLXVI. Male.
Should the bird known in Europe by tiie above name, and that found in the United States, prove to be identical, I should not be a little sur- prised, as I consider our Rough-legged Falcon and the Falco niger of WitsoN to be of the same species, the diiFerence in their colour being merely indicative of a difference in age.
While at Boston, in the winter of 1832, I offered premiums for biriis of this family, and received as many as eight at one time, of which not one resembled another in the colour of the plumage, although they were precisely similar in form and internal structure. The females were si- milar to the males, but were distinguished by their superior size. These eight birds, and some others which I examined, were all shot on the same salt marshes, within about five miles of the city. Their flight was precisely similar, as were their usual attitudes, either when perched on the branches of trees, stakes, or stalks of salt grass-hay, or when alighted on the banks of the ditches to watch for their prey. '1 he "darker the bird the more shy it was; when pursued it would fly at a much greater elevation and farther off than the light coloured indivi- duals ; and I feel confident, from my knowledge of birds, that this diffe- rence as to shyness arose from the circumstance, that the dark birds were the oldest. When listening to their disagreeable squealing notes, I could perceive no difference whatever. All these Hawks arrived in the marshes within a day or two of each other, in straggling parties of four or five, and the individuals composing these parties remained near each other as if retaining a mutual attachment. These and similar observations, made in other places from the Bay of Fundy to the marshes and meadows in the maritime districts of the State of Maryland, have convinced me that these Hawks form only one species.
The Rough-legged Hawk seldom goes farther south along our Atlantic coast than the Eastern portions of North Carolina, nor have I ever seen it to the west of the Alleghanies. It is a sluggish bird, and confines itself to the meadows and low grounds bordering the rivers and
