1 92 1.] Recently published Ornithological IVorks. 733 



Bretscher on Bird-migration in Middle Europe. 



[Der Vogelzug in Mitteleuropa. Mit 16 Karten unci vielen Tabellen. 

 Vou K. Bretsclier. Pp. 1-162. Innsbruck (Wagnersclien Univ. 

 Buclidruck.) 1920. 8vo.] 



Tn this separately-publislied memoir Mr. Bretscher en- 

 deavours to trace out the migration routes in Switzerland 

 and the neighbouring countries by an elaborate analysis of 

 all the available data. The first two chapters, comprising 

 more than half the work, deal with the spring and autumn 

 migration in Switzerland. These are followed by an 

 analysis of the spring migration in Alsace-Lorraine, Bruns- 

 wick, and Hungary, and in the final chapter the influence 

 of temperature is discussed. 



The general method employed in the case of Switzerland 

 is to divide the country into seven geographical areas, and 

 by plotting down the date of observation, according to the 

 areas and the date of the '' Zugsmittel '^ or culmination of 

 the migration-time, to discover by what route the various 

 species enter the country. In the case of the spring 

 migration the general conclusion appears to be that most 

 of the migrating birds enter Switzerland at the south-west 

 corner of the Lake of Geneva or in the north-west over the 

 Jura, and that, with the exception perhaps of the Swallow, 

 no birds cross the high ranges of the Alps from the south. 



The paper is a long one and full of details and conclusions 

 which it is impossible to summarize in a short notice, and 

 our only fear is that the data used are hardly sufficient to 

 warrant some of the conclusions arrived at. 



Chapin on new African Birds. 



[Descriptions of four new birds from the Belgian Congo. By James 

 T. Chapin. Amer. Museum Novitates, no. 7, 1921, pp. 1-9 ; 3 figs.] 



This is the fifth preliminary paper on the results of the 

 author's expedition to the Belgian Congo on behalf of 

 the American Museum of Natural History, and contains 

 descriptions of the following new forms from the Ituri and 

 Upper Uele districts : — Astur toussenellii canescens, Colius 



SEll. XI. VOL. HI. 3 C 



