flight, has a deceptive effect on most species, and makes them so little
suspicious of it,

The wide-ranging peregrine falcon is a common species in La Plata,
although, oddly enough, not included in any notice of the avifauna of
that region before 1888. The consternation caused among birds by its
appearance is vastly greater than that produced by any of the raptors I
have mentioned: and it is unquestionably very much more destructive to
birds, since it preys exclusively on them, and, as a rule, merely picks
the flesh from the head and neck, and leaves the untouched body to its
jackal, the carrion-hawk. When the peregrine appears speeding through
the air in a straight line at a great height, the feathered world, as
far as one able to see, is thrown into the greatest commo-tion, all
birds, from the smallest up to species large as duck, ibis, and curlew,
rushing about in the air as if distracted. When the falcon has
disappeared in the sky, and the wave of terror attending its progress
subsides behind it, the birds still continue wild and excited for some
time, showing how deeply they have been moved; for, as a rule, fear is
exceedingly transitory in its effects on animals,

I must, before concluding this part of my subject, mention another
raptor, also a true falcon, but differing from the peregrine in being
exclusively a marsh-hawk. In size it is nearly a third less than the
male peregrine, which it resembles in its sharp wings and manner of
flight, but its flight is much more rapid. The whole plumage, is
uniformly of a dark grey colour. Unfortunately, though I have observed
it not fewer than a hundred times, I have never been able to procure a
specimen, nor do I find that it is like any American falcon already
described; so that for the present it must remain nameless. Judging
solely from the effect produced by the appearance of this hawk, it must