324 Wonders of the Bird World 



longest at the study of ornithology are the men who know 

 what an immense amount of work there is still to be done, 

 and how little is really known ; for our acquaintance with 

 the phenomenon of migration is as yet of the slightest, and 

 we are at present but on the threshold of its investigation. 

 Much that has been written is mere guess-work, and it is 

 only where carefully-prepared statistics have been obtained 

 by the committees of experts appointed to examine into 

 the records of capture and observation, that we have any 

 real grounds upon which to form conclusions. 



The fact of migration is one with which every one of 

 us is familiar from our childhood upwards. In spring the 

 Swallows return to their northern homes, and Cuckoos and 

 other birds well-known to us, make their re-appearance in 

 England, as spring returns. In the autumn they depart and 

 are not seen again till the following spring. In the winter 

 Fieldfares and Redwings visit us from the north, and they 

 return to Scandinavia when spring comes round again. 

 All these facts are undoubted, but the exact method of the 

 migration of birds and the causes of it, still remain a very 

 interesting problem, and one which will repay the investi- 

 gation of a lifetime. 



Of one branch of the subject we now know much more 

 than our forefathers did, viz. as to the winter homes of 

 most of our British species. The enormous collection of 

 birds in our National Museum has been formed by ornith- 

 ologists for whom the geographical distribution of animals 

 has possessed a life-long interest, and the list of specimens 

 in the ' Catalogue of Birds ' can be read like a book by 

 those who understand the subject, for here is set forth in 

 line the material from which is derived the series of facts 

 which prove the geographical range of the species of birds 

 over the surface of the globe. The British Museum now 

 possesses a collection of 400,000 specimens of birds and 

 eggs, and this series is none too large for a complete study 



