t may be more simply explained. How could the
mare have known her companion was blind? What could any horse know
about such a disability? The only thing implied in the incident is the
attachment of one animal for another. The mare heard her mate calling,
probably in tones of excitement or distress, and she flew back to her.
Finding her all right, she turned toward the salt again and was
followed by her fellow. Instinct did it all.

My own observation of the wild creatures has revealed nothing so near
to human thought and reflection as is seen in the cases of the collie
and pointer dogs above referred to. The nearest to them of anything I
can now recall is an incident related by an English writer, Mr.
Kearton. In one of his books, Mr. Kearton relates how he has
frequently fooled sitting birds with wooden eggs. He put his
counterfeits, painted and marked like the originals, into the nests of
the song thrush, the blackbird, and the grasshopper warbler, and in no
case was the imposition detected. In the warbler's nest he placed
dummy eggs twice the size of her own, and the bird proceeded to brood
them without the slightest sign of suspicion that they were not of her
own laying.

But when Mr. Kearton tried his counterfeits upon a ring plover, the
fraud was detected. The plover hammered the shams with her bill "in
the most skeptical fashion," and refused to sit down upon them. When
two of the bird's own eggs were returned to the nest and left there
with two wooden ones, the plover tried to throw out the shams, but
failing to do this, "reluctantly sat down and covered good and bad
alike."

Now, can the action of the plover in this case be explained on the
theory of instinct alone? The bird could hardly have had such an
experience before. It was offered a counterfeit, and it behaved much
as you or I would have done under like conditions, although we have
the general idea of counterfeits, which the plover could not have had.
Of course, everything that pertains to the nest and eggs of a bird is
very vital to it. The bird is wise about these things from instinct.
Yet the other birds were easily fooled. We do not know how nearly
perfect Mr. Kearton's imitation eggs were, but evidently there was
some defect in them which arrested the bird's attention. If the
incident does not show powers of reflection in the bird, it certainly
shows keen powers of perception; and that birds, and indeed all
animals, show varying degrees of this p