vi The Natural History of British Ducks 
important to the scientist as the same creature in full maturity. The 
importance, too, of the moulting of birds becomes apparent when we consider 
that each moult marks a point of transition from one plumage to another, and 
a key to their relationship. The natural sequence of plumages, and moults 
too, still require elucidation in many families, whilst the times of year at 
which the moults occur, and the various modes of transition, still offer a 
broad field for investigation, in spite of the remarks of many superficial 
writers, who have stated that novel points in the ornithology of our Islands are 
not to be found. It is true that the broad lines of European ornithology 
have been well traversed, but I venture to think that there is still much work 
of permanent value to be done, and that it will be done by the specialist. 
The illustrations speak for themselves. Some few that involve the use of 
three colours are not absolutely correct, for the three-colour process has not 
yet been brought to perfection ; and it is impossible with dried skins to give 
the true colours of the soft parts ; but the defects, such as they are, are but 
slight, and, to my thinking, far more than counterbalanced by the excellence 
of all the rest of the photographs taken direct from nature. The lithographs 
by W. Greve are perfectly accurate reproductions of the original drawings, 
and were executed by the same hands that produced the admirable plates in 
Lord Lilford's book on British birds. Very gladly would I have availed 
myself more largely of Greve's process ; but the cost would have placed this 
work quite beyond the reach of the majority of those to whom I most desire 
to offer my work — the real students of Natural History, to whom every little 
detail is of interest. 
For the use of eggs and young birds in down I am indebted to my 
friend, Mr. Heatley Noble, who most generously placed his unrivalled 
collection at my disposal. I have also to thank the Hon. Walter Rothschild 
for the loan of one or two rare specimens. All the other birds figured in this 
volume were drawn from specimens in my own collection, mostly obtained by 
myself in Scotland. 
Mr. A. Thorburn has taken quite exceptional care in the preparation of 
