PREFACE. ix 
through the medium of words, but he has generally been obliged 
to employ other means, since it is difficult to do the former sat- 
isfactorily. It is probable that, were a dozen persons asked to 
express verbally any music of this kind, they would each 
employ different syllables. Many birds have two or three 
easily distinguishable combinations of musical sounds, or in 
different districts of the country have songs which are very 
distinct. The notes of many warblers, particularly those oc- 
curring in Massachusetts as migrants only, need to be learned 
and studied more than those of any other group of our avi- 
fauna. The author does not pretend to have treated these 
completely or satisfactorily, the less so that he has lost sev- 
eral memoranda. The warblers sing, however, during their 
migrations in spring, particularly in the early morning, more 
than many naturalists suppose. Mr. Allen, in the preface to 
his ‘‘Notes on Some of the Rarer Birds of Massachusetts,” 
makes the following admirable and instructive remarks on the 
variation in birds’ songs, distributions, etc. 
“Only by knowing thoroughly the fauna of a locality can 
the subsequent changes in it, induced by its becoming more 
densely settled, or by other causes, be traced. As is well 
known, the mammalian and bird faune of all the older settled 
parts of the United States are vastly different from what they 
were two hundred years ago. These changes consist mainly 
in the great decrease in numbers of the representatives of all 
the larger species, not a few of which are already extirpated 
where they were formerly common; a few of the smaller spe- 
cies of both classes have doubtless increased in numbers. Two 
causes operate unfavorably upon the larger ones; the disfor- 
esting of the country and the sporting. propensities of the 
people, everything large enough to be shot, whether useful or 
otherwise, being considered as legitimate game.” 
““Many of the water-fowl that are now only transient visit- 
ors, as the Canada Goose, the several species of Merganser, 
Teals, Black Duck and Mallard, undoubtedly once bred in this . 
state, as did also the Wild Turkey and the Prairie Hen.” 
‘In comparatively recent times, geologically speaking, prob- 
