KEl'OKT OX THE MKJKATKJX of P.lK'D.S. 395 



frag'ineuts of mij^riitioii r<mU'.s, wliicli peiiiaps can not lie bi(m<;ht into 

 continuity with those of the neighboring" regions. On the other hand, 

 ditiiculties will arise in the second case regarding the vise of the literary 

 soar(;es of information. It would seem therefore the most ])raeti('al. if 

 by a combination of tiic two methods the advantage of eac^li conld be 

 kept in view. 



In a practical view, it wonld l)e advantageous if in every country 

 all accessiWe data on the occAirence of all the species met with in the 

 region should be brought together into a national avifauna, in which 

 details also could be accurately specified in concise form. Although 

 the writer by no means under-rates the imj)ortance of such a work to 

 the poi)ulation of the country itself, yet attention must be called to the 

 general advantage which science might deri\ <' from the transhitiou of 

 such a work into other modern languages. As a model work of this 

 kind. 1 take tiie liberty to nanu' Ph'sl<e\s Oniithtxirajtliia h'ossini. 



It would also be very much to the ])ur]>ose if at tin' same tim* the 

 habitat of the individual species conld Ix' indicated cartographically, 

 as has already been done in (rermany and iSwit/.erland. By such Mork 

 the investigation of migration routes would be greatly facilitated. The 

 morecomplete the material athand, the more suitable api)ears the method 

 of determining the route of each species for itself. At least the Mi'iter 

 would unconditionally give the preference to this nu'thod. 



Finally we come to the question of the distribution of the work. The 

 writer takes the liberty to urge once more that a choice b(> made of 

 species to be investigated, because at i)resent we art^ still at the thresh- 

 old of the iuvestigation, and it seems advantageous to tii'st take up 

 the less difficult species. Among all the categories of ]»irds of passage, 

 the littoral without doubt move along tin- routes easiest to be deter- 

 mined. .Vmong the continental, on the other hand, those which avoid 

 high mountains, like the swallows and their congeners, might be easier 

 to study, 



Oue more di\ ision of work ajtpears to me ad\ isal>h'. Since e\ cry in- 

 quirer is specially iutereste<l in the species of his own country, it might 

 be suitable tor the northerners to imcstigate theii- s|)ecies with regard 

 to all their migration routes, the southerners in like manner theirs; fur- 

 ther, that the eastern si>ecies of the pahearctic region should be taken 

 up by thos«' who are masters of the literature rcdating to them. That 

 the chief interest of the Americans is directed towar<ls tlu'ii' (»wn 

 species, they have already proved by the fa<t. 



In ascertaining the migration routes of a si)eci«'S. it woidd be indis- 

 jtensably necessary to record all facts whicii (contributed to the result; 

 then only can the conclusion drawn from such premises, the migration 

 route, claim real validity. The (;artographic representation of the ma- 

 terial, when at all possible, is highly to b«' recommended. 



A model ]>rocedur(^ for the investigation of the individual species 

 can not be prescribed. It is rather to be exi»ected that eacii in<|uirer will 



