374 
The Ohio Naturalist. 
[Vol. Ill, No. 4 , 
EARLIEST OBSERVED BIRD MIGRATIONS FOR 
COLUMBUS. 
Walter J. Derby. 
In compiling and arranging the list of earliest spring migra- 
tions given in this paper, the writer has simply edited the work 
of the older observers of the club with the hope that the list will 
be of interest to other workers in Ornithology and perhaps fur- 
nish a basis for more extended study along the same line. 
The observations were all made during the years 1897 to 1902, 
and were all by members of the Wheaton Ornithological Club of 
the State University. A comparison of the data of spring migra- 
tions made by Mr. Frank M. Chapman at Englewood, New 
Jersey, which is about sixty miles farther north than Columbus, 
with this list shows that the arrival of northward-bound species 
here is from a week to ten days earlier on the average, though 
some of the dates coincide very closely and some of the records 
are from two to three weeks earlier. This difference is especially 
marked in the case of the Warbler migration which here reaches 
its height in the last week or ten days in April and the first week 
of May, while there the greatest flight occurs in the second and 
third weeks of May. The situation of Columbus is quite favor- 
able, for lying on a north and south river it is in the track of the 
northward moving migrants, and is favorably located for early 
records. An effort was made to see whether or not the data in 
this table would bear out the conclusions reached by Dr. C. C. 
Trowbridge in his article in the September number of the 
American Naturalist on “ Bird Migrations.” He was led by the 
results of a series of long and careful observations to the conclu- 
sion that wind and not temperature was the cause of bird flights. 
Since, however, the data in the possession of the writer do not 
take systematic account of the volume of migration, the only 
recourse is to periods giving especially early records or an abun- 
dance of them. Another handicap to any attempts to differenti- 
ate the effects of wind direction and temperature lies in the fact 
that in this locality high temperature is usually coincident with 
southerly and south-westerly winds, and low temperature with 
north-west and north winds. By the courteous assistance of the 
local United States Weather Bureau, statistics were obtained 
for wind direction and mean daily temperature covering the 
months of April and May, from 1898 until 1902 inclusive. An 
examination of the list of records shows a noticeable scarcity of 
records in the first two weeks of April, although both the pre- 
ceding and following weeks show several records. Comparison 
with the meteorological table shows during each year, without 
exception prevailing northerly winds and low temperature. This 
