INSTINCT AND INTELLIGENCE IN BIRDS 535 



bodies. Under such circumstances a slight error in muscular coordina- 

 tion would be fatal, and I have found fully grown and presumably 

 young birds lying dead beneath such openings, where it was evident 

 from the wounds received that death was accidental, and due to lack of 

 precision in flight. The common swift also moves with astounding 

 rapidity, as if heedless of consequences, but usually avoids every ob- 

 stacle in its path, even in waning light. It gathers the materials for its 

 twig nests while darting through the branches of a tree, with barely a 

 pause, as it bends to seize in its bill the twig, which is snapped off by 

 the momentum thus gained. Yet mistakes are sometimes made even by 

 the master swift, and I have known a case where a bird of this kind, and 

 possibly a young one, impaled itself on the sharp point of a light- 

 ning rod. 



The toothed birds of the Cretaceous period, of which Hesperornis is 

 a type, are known to have possessed a brain more nearly approaching 

 that of the reptiles in form, with large olfactory lobes. It thus seems 

 evident that the olfactory sense has lapsed and become rudimentary in 

 most modern birds. Edinger, however, maintains that since birds pos- 

 sess true, though small olfactory lobes, they must smell, but behavior 

 seems to afford the better criterion in such a case. Whatever the advo- 

 cates of the eye and the nose may have to offer in the future in regard 

 to the habits of buzzards and other old and new world scavengers, 

 repeated experiment has convinced me that the common birds of the 

 country, can not detect their young at a distance of three feet, unless 

 they either see or hear them. In fact, all of the close-at-hand, " as-near- 

 as-you-hold-a-book-to-read " observation, carried on for the past ten 

 years, some of which is to follow, has been conditioned upon the ex- 

 tremely feeble development, if not total lack of this sense. 



Ill 



The instincts of birds may be classed in a general way as (1) con- 

 tinuous instincts, which are needed for the preservation of the indi- 

 vidual, such as preying, flight, concealment and fear, however subject 

 to modification through experience, and (2) the cyclical instincts, 

 which are necessary for the preservation of the race. 



By cyclical instincts we mean those discontinuous, recurrent tend- 

 encies to action which are serial in form, and which together charac- 

 terize the reproductive cycle. They may be called, with some allow- 

 ance, the parental instincts, it being understood that this epithet is 

 used in a descriptive sense, and that there is no one kind of reaction 

 to which the term is specially applied. These instincts recur with 

 clock-like regularity in the spring and summer in the northern hemi- 

 sphere, and are subject to repetition, more or less complete, within the 

 breeding season of certain species or individuals. 



