i88o.J 
Gilbert White Reconsidered. 
633 
summer birds, are seen crossing over from Africa in spring 
and returning thither in autumn. He points out that the 
difficulties of migration are thus far less than had been 
assumed by mere book-naturalists, since “ a bird may travel 
from England to the Equator without launching out and 
exposing itself to boundless seas, and that by crossing the 
water at Dover and again at Gibraltar.” He learns from 
his brother that the swallows are careful to seledtthe easiest 
point, “ sweeping low just over the surface of the land and 
water direct their course to the opposite continent at the 
narrowest passage they can find. They usually slope across 
the bay to the south-west, and so pass over opposite to 
Tangier, which it seems is the narrowest space.” 
He notes the absence of the nightingale in Devon and 
Cornwall, which “ cannot be attributed to the want of 
warmth,” but “ is rather a presumptive argument that these 
birds come over to us from the continent at the narrowest 
passage, and do not stroll so far westward.” 
He concerns himself much with the peculiarities in the 
propagation of the cuckoo, and, though he fails to solve the 
difficulties which are here encountered, he refutes the con- 
jecture of M. Herissant that the bird was disqualified for 
incubation by the peculiar structure of the digestive organs. 
He observes a faCt which some writers of books, even in 
our own days, have scarcely mastered, viz., that birds are 
much influenced in their choice of food by colour, and con- 
sequently must be able to recognise colour. He writes — 
“ Though white currants are a much sweeter fruit than red, 
yet they [birds] seldom touch the former till they have de- 
voured every bunch of the latter,” — an assertion which 
everyone who has frequented a garden will be able to 
confirm.* 
He notices, at least as far as the swifts and swallows are 
concerned, the non-increase of birds. His explanation of 
this circumstance — i.e., that the parent birds oblige their 
young to seek new abodes — is obviously one that will not 
bear scrutiny. 
He notices the first appearance in his distridt of the cock- 
roach, — an insedt which had, indeed, been prevalent in 
London for a long time, but had not yet established itself 
in the country. It may not be here out of place to suggest 
how this vermin may have acquired its vulgar name of 
“ black beetle.” It may at first doubtless have been 
* We have often asked why, in view of the superior quality of the fruit and 
its comparative immunity from birds, is the white currant so little cultivated ? 
