Sect. XVI. 133, OF INSTINCT. 131 



For many other curious kinds of nefts fee Natural Hiftory for 

 Children, by Mr. Galton. Johnfon. London. Part I. p. 47. 



Gen. Oriolus. 



3. Thofe birds that are brought up by our care, and have had 

 little communication with others of their own fpecies, are very 

 defective in this acquired knowledge ; they are not only very 

 awkward in the conftruction of their nefts, but generally Icatter 

 their eggs in various parts of the room or cage, where they are 

 confined, and feldom produce young ones, till, by failing in their 

 firft attempt, they have learnt fomething from their own obfer- 

 vation. 



4. During the time of incubation birds are faid in general to 

 turn their eggs every day; fome cover them, when they leave 

 the neft, as ducks an3 g^e(e •, in fome the male is faid to bring 

 food to the female, that fhe may have lefs occafion of abfence, 

 in others he is faid to take her place, when fhe goes in queft of 

 food ; and all of them are faid to leave their eggs a fhorter time 

 in cold weather than in warm. In Senegal the oftrich (its on 

 her egq;s only during the night, leaving them in the day to the 

 heat of the fun ; but at the Cape of Good Hope, where the heat 

 is lefs, fhe fits on them day and night. 



If it fhould be afked, what induces a bird to fit weeks on its 

 firft eggs unconfcious that a brood of young ones will be the 

 product. ? The anfwer mull be, that it is the fame paffion that 

 induces the human mother to hold her offspring whole nights 

 and days in her fond arms, and prefs it to her bofom, uncon- 

 fcious of its future growth to fenfe and manhood, till obferva- 

 tion or tradition have informed her. 



5. And as many ladies are too refined to nurfe their own 

 children, and deliver them to the care and provifion of others ; 

 io is there one inftance of this vice in the feathered world. The 

 cuckoo in fome parts of England, as I am well informed by a 

 very diftincl: and ingenious gentleman, hatches and educates her 

 young ; whilft in other parts (he builds no neft, but ufes that of 

 fome lefTer bird, generally either of the wagtail, or hedge fpar- 

 rcw, and depositing one egg in it, takes no further care of her 

 progeny. 



M. Heriflant thought, that he had difcovered the reafon, why 

 cuckoos do not incubate their own eggs, by having obferved that 

 the crop or ftomach of the cuckoo was placed behind the fter- 

 num, or breaft-bone, and he thence fancied, that this would 

 render incubation difagreeable or impracticable. Hift. de 1' 

 Acad. Royal. 1752. But Mr. White, in his Natural Hiftory of 

 Selbourn aflerts, that on differing a fern-owl he found the fitu- 

 ation of the crop or ftomach of that bird to be behind the fter- 



num, 



