174 FRANCIS H. HERRICK 
times, and the use of any chance available means whatsoever, it 
consists in watching the conduct of young and old at their nests 
from the concealment of a tent, at a distance of usually rather less 
than three feet, and making records which shall be as complete 
as possible. These records, as a rule, cover from six to eight hours 
daily, and are continued as long as practicable, but can rarely 
be extended beyond seven or eight days. Three nests of this 
cuckoo are embraced in the present study, and are referred to 
by number, when it is necessary to designate them. 
By this and similar means I have been able to follow very closely 
the process of nest-building from start to finish in the Baltimore 
oriole, the red-eyed vireo, and other birds, and to record minutely 
the activities of nesting life in over sixt}^ cases, representing over 
thirty species of native birds, and in many of these as in the black- 
billed cuckoo, from hatching to approximately the time of flight 
of the young. 
3. THE CUCKOO OF EUROPE 
Since it will be necessary to compare the habits of Cuculus 
canorus and of the American cuckoos as closely as possible, I 
shall endeavour to give here a concise history of the former, 
emphasizing such statements of fact as seem to be most perti- 
nent and trustworthy, or to call for criticism. 
The literature of the European cuckoo is both ponderous and 
perplexing, and so far as I am aware no fairly complete bibli- 
ography, which would doubtless fill a good-sized volume, has ever 
been attempted. I can only hope that the best, if but a fraction 
of these writings, most of which can be of no value to the modern 
student who looks only for exact and reliable data, have come un- 
der my eye. Among the older accounts of the last century per- 
haps the best was that given in 1840 by MacGillivray,^ who also 
figured in his careful manner the digestive and reproductive 
organs of this bird. Of the more recent histories probably the 
^ MacGillivray, Wm. A history of British birds. Vol. 3, pp. 105-140, pi. 16, 
London, 1840. 
