THESES. JAKOB HEGYFOKY. 



„Subalpine stations have the latest dates, without regard to geogra- 

 phical position". („Aquila" VII, 1900. p. 365.) 



„The whole settling needs a comparatively long period — in the case 

 of Hirundo rustica it varies from 60 to 70 days": oscillation. („Aquila" 

 VII. 1900. p. 363.) 



„The oscillation therefore is also a biological symptom and does 

 not result solely from erroneous observations". („Aquila" VII. p. 363.) 



„The general oscillation in the course of the settling can be proved 

 even in the smallest area from one village to another, and shows that 

 neither phenological, nor geographical, but only biological factors are 

 the cause" of it. 



JAKOB HEGYFOKY: 



Progress in the department of Bird-Migration. 



According to ten years'data(l 890/91, 1894/1 901 ),comprising 10,053 

 cases, the Swallow (Hirundo rustica) arrived in Hungary on the 7th of April. 



The temperature of April 7th, according to 24 hours' reading at 

 sea-level, and based upon 45 years' observations of seven stations, was 

 9-9" C, and that on a spot of the country which is geographically deter- 

 mined by 47" r N. L. and 37" 2' E. L. from Ferro. (The years 1890 

 and 1891 yielded as mean day of arrival the 4'9th of April and a mean 

 temperature of 94 C". „Aquila" II. p. 128, 136.) 



The 10,053 data of arrival divide into 1 3 Pentades* (between March 

 7 — 1 1 and May 6 — 10). In the beginning only a few data are noticed, 

 then they get more and more numerous, till they reach culmination 

 between April 6 — 10 (with 25.3 percent); after this they become scarcer. 

 The same results as in the case of the Swallow were gained in that of 

 13 other species of Birds. („Aquila" X. p. 196.) 



* „Pentade" is a period of 5 to 6 days, into wliicli tiie Migration-period is divided, in 

 order to be able to compare or rattier to determine even smaller parts of time. 



Deo 26 0Z9 



