SIBLEY: ORNITHOLOGY 537 



birds. This concept was eventually disputed by E. F. von Homeyer (1881) who 

 concluded that migratory birds merely followed a definite direction and that 

 the members of a given species pass through Europe on a broad front, the width 

 of which is equal to the width of the breeding territory. lie also stressed that 

 the migratory direction is northeast-southwest and that the "flyways" of Palmen 

 were the result of birds being forced together into narrow flight lines in moun- 

 tain passes or other topographic features. 



Although some of his conclusions have been found in error, it was Heinrich 

 Gatke (b. 1814, d. 1897) who gave the study of migration its greatest stimulus 

 during the latter years of the nineteenth century. For fifty years he resided 

 on the island of Helgoland and made observations on the hordes of migrants 

 which paused there during the spring and fall flights. In 1891 he summarized 

 the ideas gained from his half century of observation. Gatke agreed with von 

 Homeyer that migration was on a broad front. He also developed the curious 

 idea that some species which nested in Siberia reached their African wintering 

 area by flying first west to England and then south to Africa. In the spring 

 Gatke believed that they followed the hypotenuse of the triangle, northeast from 

 Africa to Siberia. 



Recognizing the need for cooperation, Anton Reichenow and a group of col- 

 leagues had (1875) called for help from all German ornithologists to fill gaps in 

 the knowledge of German birds. Migratory routes were of special interest. Be- 

 ginning in 1877 the results were published in the Journal filr Ornithologie. The 

 practice was soon copied in England, where a committee for the study of bird 

 migration was formed. Its first report appeared in 1879. The Ornithological 

 Society of Vienna founded a committee on ornithological observation in 1882 

 and in 1883 the American Ornithologists' Union appointed the Committee on 

 Bird Migration at the first annual meeting of the Union. C. Hart Merriam was 

 the first chairman of the committee. 



These developments caused Rudolph Blasius and Gustav von Hayek of 

 Austria to develop a plan for a world-wide network of ornithological observers. 

 Crown Prince Rudolph of Austria commissioned them to organize the First In- 

 ternational Ornithological Congress, which met in Vienna in 1884. Blasius be- 

 came the chairman of a committee to organize the observers of the world and 

 the publication Ornis was founded and first published in 1885. The undertaking 

 did not succeed long. The mass of uncritically accepted data was of greatly 

 variable value and no one was willing to undertake its analysis. By 1890 the 

 various branches had again become autonomous. 



In America the Committee on Bird Migration had enthusiastically set to 

 work. Merriam's energy and knowledge had combined to push the project along. 

 By 1885 the job had grown too large for the American Ornithologists' Union 

 and in 1886, when Merriam became head of the Division of Economic Orni- 

 thology and Mammalogy, the migration studies were continued under govern- 

 mental auspices. In 1888 Wells W. Cooke (b. 1858, d. 1916), who eventually 

 became the "bird migration expert" of the Bureau of Biological Survey, pub- 

 lished his classic report on migration in the Mississippi Valley. This paper at- 

 tempted to correlate weather data with observations on migration and marked 

 the beginning of such investigations in North America. 



As valuable and important as these studies were, they were limited by the 



