THESES. GASTON DE QAAL. 



„After a mild winter the spring movement generally takes place 

 earlier". („Aquila" II. 1895. p. 74.) 



„A severe winter retards the spring-movement." („Aquila" 111. 1896. 

 p. 113.) 



„The stock of arrival-data, as collected by means of our observation- 

 stations, cannot be considered throughout as „Migration-data-stock", 

 but is more a mixture of Migration- and Distribution-Phenomena, the 

 latter prevailing." („Aquila" VII. 1900. p. 362.) 



„Consequently this Phenomenon, as far as we are able to perceive it 

 by our senses, is not so much a characteristic of Migration, as rather 

 a Phenomenon of distribution and repletion. The precise separation of 

 both these elements, as far as possible, must be one of the chief objects 

 in further investigations." (ibid.) 



„In carefully observed species it is impossible to connect the dates 

 of arrival by Isepipteses or other curves." („Aquila" VII. 1900. pp. 

 366, 370.) 



„Supported by the data of a few but well-observed species we may 

 expect to obtain better results in further observations on Migration." 

 („Aquila" II. 1895. p. 80., VII. 1900. p. 371.) 



„With regard to Hirundo rustica in Hungary one cannotspeak either 

 of „Migration-routes" or of „front-migration", but only of a gradual 

 settling in the breeding area, resembling the work of a sower". („Aquila' 

 VII. 1900. p. p. 360-370 and II Taf, XXX.) 



This refers of course to the Swallows breeding in our vicinity and 

 not to those passing to more northern regions. Cf. the observations 

 of Howard Irbv at Gibraltar (v. Otto Herman. 26.) 



Altitude has a marked retarding influence, on every species. (Total, 

 result from the regions* of Otto Herman.) 



* Hungary is orographically divided into four Migration-regions, each characterised 

 by its dates for arrival: I. Plains: earliest; II. Transdanubian district: somewhat later; 

 III. Eastern elevation; later than II ; IV. Northern elevation; latest. 



esi 25 sa 4 



