206 BRITAIN'S BIRDS AND THEIR NESTS. 



both the eggs and the sitting bird are very inconspicuous. 

 After eighteen days'" incubation the eggs are hatched. 

 Among the Picariae, blind, naked, and helpless nestlings 

 are usually found. But the present species is an excep- 

 tion in this respect, for the young are thickly covered 

 with grayish down, and are fairly active from the first. 

 Yet they are for some time entirely dependent on their 

 parents for food. 



An absurd but ancient and widespread popular super- 

 stition is expressed in the name ' Goat-Sucker."* Other 

 popular names are 'Evejar,' ' Puckeridge,'' 'Wheel -Bird' 

 (from the whirring note), ' Night-Hawk,' * Dor-Hawk,' 

 'Fern-Owl,' and 'Churn-Owl.' With regard to the last 

 two, we may say that the Nightjars are not without resem- 

 blance to the Owls both in nocturnal habits and in general 

 appearance. Modern researches, moreover, have shown that 

 there must be a real, if distant, relationship between the 

 two groups. 



Family, CYPSELID^ (Swifts). 



THE SWIFT 



(Cypselus apus). 



Plate 64. 



Surely no name could be more appropriate than that 

 of 'Swift' applied to the familiar British bird which 

 bears it ! For sheer velocity of flight it and its near 

 allies must be absolutely imrivalled. We have never 

 seen any attempt at an accurate computation of its speed, 

 and indeed the practical difficulties to be overcome are 

 very great ; but some writers have not hesitated to hint 

 at two hundred miles an hour, and from rough estimates 



