INSTINCTS OF BIRDS. 259 



their actions are instinctive. That this is actu- 

 ally the case I shall attempt to shew, though it 

 must be admitted that they are occasionally 

 modified, in a considerable degree, by the ex- 

 ercise of the intellectual faculties. 



I will not occupy the time of the Society in 

 examining the many vague and contradictory 

 opinions, which have been entertained with regard 

 to the nature of instinct by the various authors 

 who have written on the subject, being con- 

 vinced, that they are purely speculative, and 

 tend to retard, rather than advance the progress 

 of science. We must not, however, pass un- 

 noticed, the sophistical doctrine, so ingeniously 

 maintained by Dr. Darwin, in Zoonomia,* that 

 what is usually termed instinct in animals, has 

 reference to the powers of intellect solely ; since 

 the feathered tribes, notwithstanding the highly 

 curious and unequivocal examples of instinctive 

 actions which they exhibit, have furnished liim 

 with some of his most plausible arguments in 

 support of it. 



Depending on the assertion of Kircher,t that 

 young nightingales, when hatched by other 

 birds, never sing till they are instructed, and 



* Sec the Section on Instinct. Vol. 1. 

 t Dc Musurgia, Cap. dc Lusciniis. 

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