INTRODUCTORY 
ii 
succeeding season. By 1920 I had gained sufficient 
knowledge of the ways of the Cuckoo to make 
possible the successful filming of her actions in 
1921. A perusal of the detailed account of my 
experiences will show clearly how that consumma- 
tion was reached and will throw light upon many 
points which have hitherto been either obscure 
or unsuspected. 
In a paper published in the Ibis of April, 1917, 
Major R. F. Meiklejohn (who was wounded and 
taken prisoner during the retreat from Mons) 
eloquently expressed the difficulties of finding 
really satisfactory conclusions to the fascinating 
Cuckoo problems. On that account I quote his 
preliminary remarks in full — 
“ In the ignorance which still prevails regarding 
many details of the breeding habits of the Cuckoo, 
we have a good object lesson of how well Nature 
is able to guard her secrets, since, after years of 
careful and methodical investigation by distin- 
guished naturalists, comparatively few authentic 
facts have been established. 
“ Theories, indeed, have multiplied exceedingly, 
as is inevitable when facts are few. Many of these 
theories verge on the fantastic, while others have 
been evolved by an apparent confusion of cause 
and effect, and facts have been twisted to fit them. 
