268 BRITISH BIRDS. 



the others dusky, marked with alternate spots of 

 white on each side of the shaft; legs short and 

 yellow ; toes, two forward, two backward : the 

 outer one capable of being* directed forward or 

 backward at pleasure; claws white. 



The Cuckoo visits us early in the spring; the 

 well known cry of the male is commonly heard 

 about the middle of April, and ceases at the end 

 of June; its stay is short, the old birds quitting 

 this country early in July. 



Whether Cuckoos pair is not known, but it is 

 certain that they build no nest; and what is more 

 extraordinary, the female deposits one of her eggs 

 (of which she lays from four to six during the 

 season) in the nest of some other bird, by w r hom 

 it is hatched. The nest usually chosen for this 

 purpose is that of the Titlark, and it is said also 

 in those of the Hedge Sparrow, Water Wagtail, 

 Yellow-hammer, Green Linnet, or Whinchat; the 

 first is more certainly known to be preferred.* 



We owe the first satisfactory account f of the 

 singular economy of this bird, in the disposal of 

 its egg, to Mr. Edward Jenner, afterwards Dr. 

 Jenner, the illustrious discoverer of Vaccination. 

 The following being the result of repeated obser- 

 vations and experiments, accurately made by him- 

 self, we shall detail it as nearly as possible in his 

 own words. 



During the time the Hedge Sparrow is laying 

 her eggs, which generally takes up four or five 



* The author could never find the egg of the Cuckoo deposited 

 in any nest but in that of a Lark, which is always on the ground. 



t Vide Transactions of the Royal Society, Vol. LXXVIIL, 

 Part II. 1787. 



