48 
cause of their voluminousness ; nor is it necessary to do so in the pres- 
ent connection. The prime object to be attained is a complete knowledge 
of the movements of each species. Such knowledge can be gained only 
by the accumulation of the facts noted by many observers over a term 
of years. The facts so accumulated will serve as a guide to the time of 
the appearance and disappearance of each species, and also will serve 
as a check to the observers’ records. By this means the observers will 
be enabled to correct many mistakes into which they will fall, and will 
be guided to record many interesting facts which otherwise would 
escape notice. 
The above points have been dwelt upon in order that no observer may. 
feel slighted should he not find credit given for all his observations. 
For example, some 60 or 70 stations scattered over every State in the 
district report the White-bellied Nuthatch as a resident. It is enough 
for present purposes to say that the species is resident throughout the 
Mississippi Valley. Or if, in the records of migration, 5 or 6 stations 
situated on the same parallel record the arrival of a species about the 
same time, it is more intelligible to say that on that date the van 
reached this latitude, than to give the name, latitude, and date for each 
of the stations.* 
The rule here followed is that the shorter the record the more easily it 
is comprehended, and the supposition is that the student of this report 
will always have a map before him. It is useless to attempt to study 
migration without this aid. 
The remaining or systematic portion of the report aims to be entirely 
historical rather than philosophical or theoretical ; and it must be re- 
membered tirat it is based upon notes, many of which, through lack of 
sufficient ornithological knowledge on the part of the observer, undoubt- 
‘edly are erroneous, but which, since they bear on their face the appear- 
ance of truth, have been accepted as facts. Hence, while great care has 
been taken to make the statements as accurate as possible, errors un- 
doubtedly have crept in, and the author will consider it a special favor 
if those who discover such will communicate the fact to him. 
There remains the pleasant duty of acknowledging the assistance 
received from various sources. The first acknowledgments are due to 
the observers, without whose able and united efforts nothing could have 
been accomplished. These persons have given their time and thought 
to the work without compensation, stimulated only by their love of 
nature and their interest in scientific work; and many have expressed 
the pleasure it afforded them by the statement “the enjoyment we have 
derived from the work has more than repaid us.” To Dr. C. Hart Mer- 
riam the thanks of all are due for his untiring zealin bringiug the work 
before the public and enlisting the services of observers, and for the 
[*I canvot agree with Professor Cooke in this method of treating records of mi- 
gration. Owing to the difference in altitude of stations on the same parallel, and to 
the influence of topography and other local conditions, I deem it necessary to give in 
full the exact records of each observer.—C. H. M.] 
