AT 
has just been said does not apply to Mr. Otto Widmann’s notes for 1885, 
since, as in former years, he kept a full record of all the movements of 
each species. 
In preparing this part of the report the chief endeavor has been to 
trace the movements of the van of each species, while the more im- 
portant part, relating to the movements of the bulk, must be left un- 
noticed. : 
The departure of a bird from any point is necessarily followed by its 
arrival at some other point; so that when a departure is noted a cor- 
responding arrival may be looked for. The record of a typical move- 
ment of a species in its northern migration would contain: 1st, the 
record of the earliest arrival; 2d, the arrival of the bulk of the species 
at a point somewhat farther south ; 3d, the departure of the bulk from 
a point still farther south; 4th, the departure of the last individual 
from the southern limit occupied by the species on the same day. 
Such a contemporaneous record would prove that during the previous 
night a general movement of the species had taken place. 
Were all the records as full as those of the first arrivals many such 
typical movements undoubtedly would be found. This, however, would 
be too much to expect. What we ought to find recorded is an arrival 
of the bulk of a species for each corresponding departure, and when 
the stations become sufficiently numerous, and the observers more 
thoroughly trained, these important items will be forthcoming in many 
if not in most cases. Then and not till then will something definite be 
known concerning the distance actually traveled by birds during a 
single night’s migration. The computations based on first arrivals will 
always be very uncertain, and if accurate information ever is obtained 
it must come almost entirely from the movements of the bulk. * 
In the systematic portion of this report it has been found impracticable 
to give in full all the notes contributed by the different observers, be- 
[* Again I am forced to differ with Professor Cooke. ‘There is no evidence to show 
that in any species of bird a sufficiently large proportion of the total number of individ- 
uals comprising the migratory host move forward together at one time to justify the 
description of such a movement as that of “ the bulk of the species.” On the con- 
trary, migration consists of a series of successive movements or waves, each of which 
brings a variable number of individuals to places a variable distance in advance of 
the point or points from which they started. It was the recognition of these facts 
that led me to omit reference to ‘‘ bulk” movements in preparing the circular for 1885, 
and to insert the following statement, of which Professor Cooke makes no mention: 
‘‘ The committee particularly desires exact records of every increase and decrease 
in the numbers of a given species over a given area; forit is only by the knowledge 
of the daily fluctuations of the same species in the same place that the progress and 
movements of a ‘flight,’ or ‘bird wave,’ can betraced. Such data can be contrib- 
uted by experienced observers only, and in their procurement much time must be 
spent in the field. During the progress of the migratory movement the observer 
should go over the same ground day after day, and, if possible, both early in the 
morning and late in the afternoon. He should visit woodlands, thickets of dense 
undergrowth, and open fields; and, if possible, both swamp and upland should fall 
under his daily scrutiny. ””—C. H. M.] 
