344 Eaton, Spring Bird Migratioti, igoj. \^uhi 



and ash trees were just bursting the leaf buds. On May 12 apple 

 orchards were in the height of bloom. But no great migration 

 wave had reached us. Nearly all the May migrants were from 

 four to nine days behind time. Twenty-five observers from the 

 Bird Section of the Rochester Academy of Science were scouring 

 the fields and groves, eager to make a full record of the migrations 

 at our station. The birds did not escape us unless they did it at 

 night. The nearest thing to a migration wave came on the 3rd of 

 May when forty-eight species of birds, including five species of 

 warblers, were seen by a single observer. These species were not 

 all new arrivals, but many of them were. A southerly wind had 

 prevailed throughout the preceding day and evening, but ended in 

 cool, lowering weather. Two nights before ice had frozen one- 

 fourth of an inch in thickness. 



In 1902 the greatest bird wave of the season likewise occurred 

 on the 3rd of May- when the same observer above referred to re- 

 corded seventy-five species of birds, including nineteen species of 

 warblers. That, however, was a perfect day, warm and sunny, fol- 

 lowing a low cyclonic center moving from the southwest and cul- 

 minating in a shower during the night. During the warbler season 

 of 1903 there was no decided southwest cyclonic storm and no 

 remarkable warbler wave. All concomitants of the season con- 

 spired to retard and dissipate any wave of migrants in early May. 

 No warm southwest wand swept them upon us. The gradual 

 unfolding of the leaves furnished no sudden opportunities of shel- 

 ter and insect food. The nights, being uniformly clear and free 

 from storms, did not compel the migrating hosts to halt in our 

 territory. The northern species which came to us were only those 

 which were induced to stop for rest and food as they leisurely pur- 

 sued the journey toward their breeding grounds. The result of 

 all of these causes was a gradual and uninterrupted stream of mi- 

 gration with little dash and rush and concentration. 



These facts tend to show that the shyer, foliage inhabiting birds 

 travel largely on the crests of warm waves advancing from the 

 south, and as in western New York these waves usually come from 

 the southwest, it is undoubtedly true that our birds mostly come 

 from that direction. It is not true that birds migrate ojily with the 

 aid of favoring winds ; nor when the weather gets warm enough to 



