SOME BIRD PROBLEMS 95 



the Hawk is as large as a golf ball. The reason seems obvious, 

 e.g. that if the Cuckoo produced an egg equal in size to that of 

 the Hawk no small bird upon which the Cuckoo thrusts its charge 

 would tolerate it, and the Cuckoo would defeat its own end. 

 How has this remarkable adaptation come about ? Moreover, 

 it should be remembered tfiat, in spite of the smallness of the 

 Cuckoo's egg, the newly-hatched chick, though blind and practi- 

 cally naked, is possessed of immense strength, and bundles out 

 of the nest in which it is born everything that is there beside it. 

 I would further ask concerning this species how the sexes call 

 one another, if, as is now recognised, they both utter the well- 

 known double cry, and how the young Cuckoos find their way, 

 without parental guidance, to Africa, or India, in Autumn, when 

 they have never before left the confines of one's own parish, 

 and the adult birds have preceded them by some weeks, or even 

 months ? 



It is, by the way, still believed in some country districts that 

 the Cuckoo turns into a Hawk when Summer is on the wane. 

 A Hertfordshire countrywoman told me with immense serious- 

 ness not long ago that this 'really was so. A custom in my 

 native county, too, when first hearing the Cuckoo in Spring, is 

 to throw everything one is carrying into the air and to curtsey 

 violently. I have seen this operation performed by the gentler 

 sex on more than one occasion ! 



Small birds are, during Summer, often seen flying in pursuit of 

 a Cuckoo, evidently possessed with a desire to mob it, or drive 

 it out of a district. Do the small birds know it is a Cuckoo and 

 wish to retaliate because of the parasitism it practises, or do they 

 mistake it for a Hawk ? 



The Nightjar (Caprimulgus europceus) was another bird which 

 greatly interested Gilbert White, and, whilst many old-fashioned 

 notions concerning this species have now been exploded, its pro- 

 duction of two rounded eggs, laid upon the bare ground, seems 

 to me of more than passing interest. Most British birds which 

 deposit their eggs on, or near, the ground, or make little pretence 

 at nest building (examples : Kinged Plover (Mgiditis hiaticida), 

 Lapwing (Vandlus vandlus}, Partridge (Perdix perdix) and several 

 others), produce a pear-shaped egg, and these are, except in the 

 case of the Partridge, usually four in number, so that they may 

 be placed with the small ends tapering towards the centre in 

 order to take up the least amount of space, the reason apparently 

 being that the sitting bird may cover them all successfully. 



