x PREFACE 



too, are often over-elaborate for those to whom 

 ornithology is not the main business of life. Many- 

 people, however devoted to the subject, have not 

 the time for the proper study of Dr. Gadow's great 

 work, which, moreover, being written in German, is 

 a sealed book to numbers of English readers. For 

 the study of bird anatomy they are often thrown 

 back upon the good but insufficient treatises written 

 for the use of medical students. Natural History 

 books, describing the lives of birds, are many, and, 

 not a few of them, first-rate, though, curiously, there 

 was not, to my knowledge, any English book in 

 which a general review of the known facts and of 

 the problems of migration had been successfully un- 

 dertaken, till the appearance of the second volume 

 of Professor Newton's Dictionary of Birds, containing 

 a very able article on the subject. There are several 

 books in English treating of flight. Of these 

 Professor Marey's Animal Mechanism seems to me 

 the best. But some of his most instructive experi- 

 ments have been made since its publication, and an 

 account of them is to be found only in his later and 

 larger work, Le Vol des Oiseaux. It has been my 

 wish to bring the work of the anatomist and physio- 

 logist into connection with that of the student of 

 flight and that of the outdoor naturalist. With this 



o 



object I have made some investigations and observa- 

 tions which, I believe, may lay claim to originality, 

 and I have consulted the best English, French, and 

 German books upon ornithology, as well as a number 



