374 The Ohio Naturalist. [Vol. Ill, No. 4, 



EARLIEST OBSERVED BIRD MIGRATIONS FOR 



COLUMBUS. 



WaIvTer J. Derby. 



In compiling and arranging the list of earliest spring migra- 

 tions given in this paper, the writer has simpl}- 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 stud}- along the same line. 



The observations were all n>ade during the years 1897 to 1902, 

 and were all by members of the Wheaton Ornithological Club of 

 the State Universit}-. A comparison of the data of spring migra- 

 tions made by Mr. Frank M. Chapman at Englewood, New 

 Jersej', which is about sixt}- 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 da^-s 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 earl}' 

 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 sj'stematic 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 dail}' temperature covering the 

 months of April and May, from 1898 until 1902 inclusive. An 

 examination of the list of records shows a noticeable scarcit}^ 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 



