About the thinnest, shallowest nest, for its situation, that can be found is that of the turtle-dove.  A few sticks and straws are carelessly thrown together, hardly sufficient to prevent the eggs from falling through or rolling off.  The nest of the passenger pigeon is equally hasty and insufficient, and the squabs often fall to the ground and perish.  The other extreme among our common birds is furnished by the ferruginous thrush, which collects together a mass of material that would fill a half-bushel measure; or by the fish-hawk, which adds to and repairs its nest year after year, till the whole would make a cart-load.

The rarest of all nests is that of the eagle, because the eagle is the rarest of all birds.  Indeed, so seldom is the eagle seen, that its presence always seems accidental.  It appears as if merely pausing on the way, while bound for some distant unknown region.  One September, while a youth, I saw the ring-tailed eagle, an immense, dusky bird, the sight of which filled me with awe.  It lingered about the hills for two days.  Some young cattle, a two year-old colt, and half a dozen sheep were at pasture on a high ridge that led up to the mountain, and in plain view of the house.  On the second day, this dusky monarch was seen flying about above them.  Presently he began to hover over them, after the manner of a hawk watching for mice.  He then with extended legs let himself slowly down upon them, actually grappling the backs of the young cattle, and frightening the creatures so that they rushed about the field in great consternation; and finally, as he grew bolder and more frequent in his descents, the whole herd broke over the fence, and came tearing down to the house “like mad.”  It did not seem to be an assault with intent to kill, but was, perhaps, a stratagem resorted to in order to separate the herd and expose the lambs, which hugged the cattle very closely.  When he occasionally alighted upon the oaks that stood near, the branch could be seen to sway and bend beneath him.  Finally, as a rifleman started out in pursuit of him, he launched into the air, set his wings, and sailed away southward.  A few years afterward, in January, another eagle passed through the same locality, alighting in a field near some dead animal, but tarried briefly.

[Illustration:  EAGLE.]

So much by way of identification.  The bird is common to the northern parts of both hemispheres, and places its eyrie on high, precipitous rocks.  A pair built on an inaccessible shelf of rock along the Hudson for eight successive years.  A squad of Revolutionary soldiers also found a nest along this river, and had an adventure with the bird that came near costing one of their number his life.  His comrades let him down by a rope to secure the eggs or young, when he was attacked by the female eagle with such fury that he was obliged to defend himself with his knife.  In doing so, by a mis-stroke, he nearly severed the rope that held him, and was drawn up by a single strand from his perilous position.  Audubon, from whom this anecdote is taken, figures and describes this bird as the golden eagle, though I have little doubt that Wilson was right, and that the golden eagle is a distinct species.