lb MR. T. SOUTHWELL ON MIGRATION OTHER THAN OF BIRDS, 
by our friend Professor Newton in conjunction with his 
brother Edward, and speedily led to the interesting discovery 
that the common Song Thrush is a migratory species. Since 
then it has been established that there is hardly a sedentary 
species of bird found in the British Isles, and that all are 
subject to migratory movements to a greater or less degree, 
and strange as it may seem, one of the most pronounced 
migrants is the tiniest of all our indigenous birds, the Gold 
Crested Wren. 
Much has been done by British and Continental observers 
to throw light upon the periodic movements of birds and the 
routes followed by them, and Mr. Eagle Clarke has spent 
months immured in lighthouses, or tossing in the light- 
vessels off our coast, in pursuit of such information, and in 
addition, who can say how many midnight hours he has 
devoted to analysing the results of his own and others’ 
observations ? We know that although in many cases they 
are highly complicated, the main routes of migration are in 
spring towards the north and from west to east, and in 
autumn from north to south and east to west ; but here our 
knowledge stops. We look at the clock and see the time 
clearly indicated by the revolving hands, but this gives us 
no clue to the nature of the machinery hidden behind the 
dial which propels those hands, so, although we may have 
learned much as to the seasons and direction of their journeys, 
the cause which prompts these migratory movements, and 
the wonderful faculties which lead the birds on these often 
protracted and always perilous journeys are still very largely 
matters of conjecture. Efforts to solve the mystery have 
been many, and it is possible that there are grains of truth 
scattered here and there in the mass of theory that has been 
advanced, which may at some future period aid in solving 
the problem ; but at present wise men fear to tread where 
their more ardent, if not better informed brethren, rush in, 
and we can only at present veil our ignorance by the use 
of a term which has never yet been satisfactorily defined, 
and attribute the wonderful phenomena to inherited 
“ instinct.” 
