306 Wonders of the Bird World 



was taken of the fact at the time, but when the eggs came 

 to be blown, it was discovered that they were hard-set, and 

 had fully-developed embryos inside. On blowing the large 

 egg, the unmistakable zygodactyle foot of a Cuckoo pro- 

 truded from the opening, with its toes arranged in pairs, 

 two in front and two behind. No Redstart has such a foot, 

 as it is a Passerine bird, with three toes in front and one 

 behind. 



That Cuckoos recognize their foster-parents after a long 

 period seems to be equally certain, for the late Mr. A. D. 

 Bartlett, the Superintendent of the Zoological Gardens, 

 used to tell the story of a young Cuckoo which was brought 

 to the " Zoo " in the autumn, and lived through the winter, 

 which is a very rare occurrence in this country. All those 

 that I have tried to rear have flourished for a short time, 

 but have beaten themselves to death or pined away when 

 the season of their migration came on. The one which 

 survived through the winter in the Gardens was, therefore, 

 looked upon as an exceptional bird, and was prized 

 accordingly. By the following spring it was in fine 

 plumage, and used to call " cuckoo " in the aviary to all 

 appearance, in fact, it was a thoroughly adult bird. It was 

 determined by the keeper, Travis, whom most of us 

 remember well, to introduce into the Western Aviary 

 several British species, and amongst the latter was a 

 Hedge-Sparrow. No sooner was the latter admitted than 

 the Cuckoo, which had lived for months in the Gardens, 

 and was perfectly able to feed itself, fluttered down to the 

 little Hedge-Sparrow, and began with open mouth to 

 clamour to be fed. Who can doubt that this Cuckoo had 

 originally been brought up by Hedge-Sparrows, and that 

 it recognized at once the species which had been its foster- 

 parent ? 



Of the date when the old birds begin to leave the 

 country nothing is exactly known, but they undoubtedly 



