n tried.

When an animal is killed in the country, it is well known that the
condors, like other carrion-vultures, soon gain intelligence of it,
and congregate in an inexplicable manner. In most cases it must not be
overlooked, that the birds have discovered their prey, and have picked
the skeleton clean, before the flesh is in the least degree tainted.
Remembering the experiments of M. Audubon, on the little smelling
powers of carrion-hawks, I tried in the above-mentioned garden the
following experiment: the condors were tied, each by a rope, in a long
row at the bottom of a wall; and having folded up a piece of meat in
white paper, I walked backwards and forwards, carrying it in my hand
at the distance of about three yards from them, but no notice whatever
was taken. I then threw it on the ground, within one yard of an old
male bird; he looked at it for a moment with attention, but then
regarded it no more. With a stick I pushed it closer and closer, until
at last he touched it with his beak; the paper was then instantly torn
off with fury, and at the same moment, every bird in the long row
began struggling and flapping its wings. Under the same circumstances,
it would have been quite impossible to have deceived a dog. The
evidence in favor of and against the acute smelling powers of
carrion-vultures is singularly balanced. Professor Owen has
demonstrated that the olfactory nerves of the turkey-buzzard
(_Cathartes aura_) are highly developed; and on the evening when Mr.
Owen's paper was read at the Zooelogical Society, it was mentioned by a
gentleman that he had seen the carrion-hawks in the West Indies on two
occasions collect on the roof of a house, when a corpse had become
offensive from not having been buried: in this case, the intelligence
could hardly have been acquired by sight. On the other hand, besides
the experiments of Audubon and that one by myself, Mr. Bachman has
tried in the United States many varied plans, showing that neither the
turkey-buzzard (the species dissected by Professor Owen) nor the
gallinazo find their food by smell. He covered portions of highly
offensive offal with a thin canvas cloth, and strewed pieces of meat
on it; these the carrion-vultures ate up, and then remained quietly
standing, with their beaks within the eighth of an inch of the putrid
mass, without discovering it. A small rent was made in the canvas, and
the offal was immediately discovered; the canvas was replaced by a
fr