iHoofe jBtetos and S^ebtetDs 



Instinct and Intelligence in Birds. By 

 Francis H. Herrick. Popular Science 

 Monthly, igio; Part I, June, pp. 532- 

 556; Part II, July, pp. 82-97; Part III, 

 August, pp. 1 22-141. 



Professor Herrick bases his discussion of 

 instinct and intelligence in birds, in the 

 main, on his detailed studies of the nesting 

 habits of certain species, the results of 

 which have been presented in his 'Home- 

 Life of Wild Birds.' He deals, therefore, 

 only with that part of the birds' year 

 which embraces the season of reproduction. 

 This he terms the breeding cycle. In it 

 are exhibited the "cyclical instincts," in 

 which are included the following activities: 

 I. Migration to Breeding Area. 2. 

 Courtship and Mating. 3. Nest-building. 

 4. Laying Eggs in Nest. 5. Incubation 

 and Care of Eggs. 6. Care of Young in 

 Nest. 7. Care of Young out of Nest. 

 8. Migration to Feeding Area. 



"It is evident," Professor Herrick 

 remarks, "that these serial instincts must 

 be in relatively perfect harmony, or if 

 regular perturbations occur, new and 

 permanent adjustments must be forth- 

 coming to meet them, if the species s to 

 continue to exist. One act, or series of 

 related acts, must be performed in prepa- 

 ration for that which follows. The nest 

 must 'anticipate' the eggs and not the 

 eggs the nest. Upon the whole," he 

 continues, "the serial instincts of birds 

 are well attuned, yet disturbances more 

 frequently occur than is commonly 

 supposed, and by conditions of this 

 kind much that is anomalous or eccen- 

 tric in the behavior of birds can be ex- 

 plained . . ." 



If the orderly development of these 

 instincts be prevented, certain acts may be 

 repeated. Thus, if the nest and eggs of an 

 incubating bird be destroyed, it may 

 rebuild, lay a second set of eggs, and 

 resume incubation, thus repeating activi- 

 ties 3, 4 and 5. With two-brooded birds 

 such repetition is normal. 



The Yellow Warbler's well-known habit 



of building over a Cowbird's egg which 

 has been laid in its nest is attributed to 

 a break in the cyclical instincts, which 

 have been interrupted by the intrusion of 

 the strange egg. 



The absence of the nest-building 

 instinct in the Cowbird is believed to be 

 due to "lack of attunement" in the cycli- 

 cal instincts, resulting in the premature 

 appearance of the egg and the conse- 

 quent necessity of using the nest of 

 another bird if the species is to be per- 

 petuated. A further factor in the devel- 

 opment of such parasitism is the long 

 interval between the laying of the eggs, 

 such as is said to occur with the Euro- 

 pean Cuckoo. 



Professor Herrick's discussion of this 

 subject is novel, and his theory seems 

 better grounded and more worthy of 

 acceptance than any which has hereto- 

 fore been advanced. 



In short, without going into further 

 detail, we may simply add that his whole 

 paper contains much that is interesting 

 and suggestive, and we commend it to 

 the many bird students who are some- 

 what at a loss as to the channel into which 

 they may best turn their energies. Its 

 value to them would, however, have been 

 greatly increased by a concise statement 

 of the problem in hand, and of conclu- 

 sions arrived at in regard to it. In default 

 of a summary, one is somewhat at a loss 

 to learn just what opinion has been 

 reached. On page 536, of Part I, we are 

 told that "the whole fabric of instinctive 

 life is subject at nearly everj- step to the 

 modifying influence of intelligence," but 

 on page 138 of part III it is said that 

 birds "seldom meet emergencies by doing 

 the intelligent act." Nevertheless it is 

 inferred from the character of the bird's 

 brain (p. 534, Part I) "that, while birds 

 are intelligent and able to form associa- 

 tions of some sort freely, they must be 

 animals in which the instincts are devel- 

 oped to an extraordinary degree of 

 perfection . . ." — F. M. C. 



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