112 INTELLIGENCE 
resentment, but Kingbirds attack every Crow which ventures near their 
nest, often pursuing them for several hundred yards. 
Similar instances, illustrating the wide range of intelligence among 
birds of different species, might be multiplied endlessly, but any consider- 
ation of the subject renders this variation so evident that it is assuredly 
unnecessary to present further proof. 
Variation in intelligence is not confined to these differences between 
species, but within narrower limits is shown by the individual. To those 
who study birds as individuals rather than as species, this statement 
will seem superfluous, but advocates of automatic bird-life would have 
us believe that, in the same species, one bird is essentially the duplicate 
of another. Birds which nest, closely associated in colonies, where a 
certain standard of behavior is developed by similarity of environment 
and imitation, show less individuality than those species of more sol- 
itary habits; but it requires only intimate experience with representatives 
of either class to convince one that pronounced characteristics are often 
shown by certain individuals, and indeed one rarely finds in the latter 
group two birds which act exactly alike. It is the range of intelligence 
among the individuals which, in the end, determines the degree of 
success of the species. It is among the Passerine birds that we shall find 
birds possessing the highest intelligence, and the Passeres are the birds 
of the day, the dominant group in the Class Aves, outnumbering the 
members of all other orders combined. 
Admitting then that some species of birds exhibit barely a glimmer 
of intelligence, and are indeed very near to being feathered automata, 
are there not at the other end of the scale birds which possess the power 
to reason? . 
By reason, accepting Lloyd Morgan’s definition, is meant the “‘pro- 
cess of drawing a logical inference,’’ the ability ‘‘to think the therefore.” 
We can of course determine the bird’s mental status only on the basis 
of its actions. Birds’ notes, so far as we understand them, express only 
primary emotions. If birds then can draw an inference, we can be 
aware of it only through its effect on their behavior. Those direct 
responses to conditions which lead to change of action, or of habit, 
as where a bird becomes shy through persecution or tame through pro- 
tection, are not to be attributed to reason, as the term is here used, but 
are unreasoning exhibitions prompted by sense associations which 
oceasion no sequence of thought on the part of the bird, no drawing of 
conclusions or performance of acts made with such indubitable reference 
to other following, dependent acts, that it is evident the latter were con- 
ceived of as the logical consequence of the former. The bird, with truly 
wonderful quickness, learns to associate a certain thing with danger, 
another thing with safety. The Pelicans of Pelican Island, Florida, 
for the first time in their known history, failed to return to their island 
because a sign had been erected on it. This illustrates the keenness of 
the birds’ perception, but it also demonstrates their inability to infer 
that a piece of board was harmless. 
