_To the Editor of Birds and All Nature_:
SIR: Are you not mistaken in the assertion in your October number that
vultures, carrion-crows, etc., have such keen scent that they can
detect carcasses and offal at a very great distance?
I was under the impression that Wilson[1] had decided this forever,
and proved conclusively that their apparently miraculous power of
discovering their proper food, was due to keenness of vision, and not
of the sense of smell.
The following extracts may be new to some and interesting to all of
your readers: Under the head "_Vultur aura_, Turkey Vulture," etc., I
find:
"Observations on the supposed power which vultures such as the turkey
vulture, are said to possess of scenting carrion at a great distance.
"It has always appeared to us unaccountable that birds of prey, as
vultures, could scent carcasses at such immense distances, as they
are said to do. We were led to call in question the accuracy of this
opinion, on recollecting the observations of some travelers, who have
remarked birds of prey directing their course towards dead animals
floating in the rivers in India, where the wind blows steadily from
one point of the compass for months in succession. It was not easy to
conceive that the effluvium from a putrid carcass in the water, could
proceed in direct opposition to the current of air, and affect the
olfactory nerves of birds at so many miles distant. We were disposed to
believe that these birds were directed towards the carrion rather by
the sense of seeing than by that of smelling. This opinion is confirmed
by the following observations of our friend Audubon, communicated to us
by him some time ago for our _Philosophical Journal_."
Here follows at length Audubon's communication, from which I extract
the following passages:
"My _First Experiment_ was as follows: I procured a skin of our common
deer, entire to the hoofs, and stuffed it carefully with dried grass
until filled rather above the natural size,--suffered the whole to
become perfectly dry and as hard as leather--took it to the middle of a
large open field, and laid it down upon its back with the legs up and
apart, as if the animal were dead and putrid. I then retired about a
few hundred yards, and in the lapse of some minutes a vulture coursing
around the field, tolerably high, espied the skin, sailed directly
towards it, and alighted within a few yards of it. I ran immediately,
covered by a large tree, until within about forty yards, and from that
place could spy the bird with ease. He approached the skin, looked at
it without apparent suspicion, raised his tail and voided itself freely
(as you well know all birds of prey in a wild state generally do before
feeding), then approaching the eyes, that were here solid globes of
hard, dried, and painted clay, attacked first one and then the other,
with, however, no farther advantage than that of disarranging them.
This part was abandoned; the bird walked to the other extremity of the
pretended animal, and there, with much exertion, tore the stitches
apart, until much fodder and hay were pulled out; but no flesh could
the bird find or smell; he was intent on finding some where none
existed, and, after reiterated efforts, all useless, he took flight,
coursed round the field, when, suddenly turning and falling, I saw him
kill a small garter snake and swallow it in an instant. The vulture
rose again, sailed about, and passed several times quite low over the
stuffed deer-skin, as if loth to abandon so good-looking a prey.
"Judge of my feelings when I plainly saw that the vulture, which could
not discover through its extraordinary sense of smell that no flesh,
either fresh or putrid, existed about that skin, could at a glance see
a snake scarcely as large as a man's finger, alive, and destitute of
odor, hundreds of yards distant. I concluded that, at all events, his
ocular powers were much better than his sense of smell.
"_Second Experiment._--I had a large dead hog hauled some distance from
the house and put into a ravine, about twenty feet deeper than the
surface of the earth around it, narrow and winding much, filled with
briars and high cane. In this I made the negroes conceal the hog, by
binding cane over it, until I thought it would puzzle either buzzards,
carrion-crows, or any other birds to see it, and left it for two days.
This was early in the month of July, when, in this latitude, a body
becomes putrid and extremely fetid in a short time. I saw from time to
time many vultures, in search of food, sail over the field and ravine
in all directions, but none discovered the carcass, although during
this time several dogs had visited it and fed plentifully on it. I
tried to go near it, but the smell was so insufferable when within
thirty yards of it that I abandoned it, and the remnants were entirely
destroyed at last through natural decay.
"I then took a young pig, put a knife through its neck, and made it
bleed on the earth and grass about the same, and, having covered it
closely with leaves, also watched the result. The vultures saw the
fresh blood, alighted about it, followed it down into the ravine,
discovered by the blood of the pig, and devoured it, when yet quite
fresh, within my sight."
He pursues the subject at some length, recounting other experiments;
but these, were they not even given on the authority of
Audubon--_clarum et venerabile nomen_--seem to me to be conclusive.
_22 Irving place, New York_