170 
FRANCIS H. HERRICK 
has excited more interest among naturalists and people generally, 
or about which more has been written, and it must be added, 
too often foolishly written, in both ancient and modern times. 
This interest is primarily due to its ' clever trick ' of foisting its 
own eggs upon other species of birds, which usually accept them 
and become foster-parents to their young though at great cost 
for the price of rearing every cuckoo is the total and invariable 
destruction of the offspring of the dupe. But this is not the only 
anomalous conduct in the life of these birds, which seem to break 
more rules than most of their kind. Of more interest to the biol- 
ogist and psychologist are the accounts, whether accepted at 
face-value or not, of the ways in which the cuckoo seems to scheme 
to accomplish her ends, to smuggle her egg into a proper nest at 
the proper time, and even to watch the result. 
The striking fact that the European cuckoo builds no nest of its 
own, but steals one instead, that the same bird lays but one egg in 
a given nest, and that its young are reared by nurses was reported 
by Aristotle. For over two thousand years since, the question 
has been repeatedly asked: '^Why does not the cuckoo brood?" 
Speculation has been rife, as is usually the case where the facts 
are insufficient to trace the history of the origin of a habit or 
instinct, and a satisfactory answer to the question is not to be 
found in the many and varied theories and conjectures which 
have been given from the times of Aristotle and Pliny to those of 
Darwin and Baldamus.^ iVfter giving a history of opinion on 
this subject and a summary of what he regards as the established 
facts, the latter concludes his long monograph on the cuckoos of 
the w^orld with the following words: ^^All answers to the wider 
questions of how and why, in my opinion, can be based only on 
conjectures: and, however clever many of these may be, for exact 
science they have scarcely any value at all." 
For many years the present writer has been looking for an op- 
portunity of studying the instincts and general habits of the Ameri- 
can cuckoos, in the hope that in their behavior a key might be 
^Baldamus, A. C. Eduard. Das Leben der europaischen Kuckucke, nebst Beitra- 
gen zur Lebenskunde der iibrigen parasitischen Kuckucke u. Starlinge. pp. i- 
viii, 1-226, mit 8 Farbendrucktafeln. Berlin, 1892. 
