PREUMINARIES 
31 
halts which offer opportunities of catching them in masses, 
their flying in flocks tempts men to throw his catching appa- 
ratuses in their way, using the victims as food and employing 
their feathers for industrial i. e. commercial purposes. ' 
^Consequently birds of passage, in certain southern coun- 
tries, form periodical ^popular food"; and the number of 
victims that fall a prey is proportionate to the increase in 
the dimensions of the catching apparatuses that grow with 
the development of industry, while the perfection of the means 
of transport has done much to render the realisation of the 
booty easy." 
„The transformation of the agricultural conditions already 
referred to has also had its part in diminishing the numbers 
of birds of passage, by depriving them of the requisites of 
peaceful nesting." 
„The place of the birds of passage that, according to the 
season, wander from North to South and vice-versa, in the 
order of Nature justifies the international control of this phase 
of bird-protection." 
It is quite natural that such a transformation of things 
produced results which, in the second half of the XIX*'' century, 
had already made themselves felt in no small measure. Side 
by side with the humanitarian, often sentimentalistic protection 
of birds which was particularly prominent in Germany and 
was made part and parcel of a general protection of animals, 
the necessity of rational bird-protection, that had its main- 
spring in the economic i. e. material interests of man, began 
to make headway; this feeling was naturally most prominent 
in countries where the results of conditions favourable to 
birds, of which we have just made mention, had made 
themselves most felt. 
