THESES. JAKOB HEOYFOKY. 



Six pentades before the culmination show 41 "5, the six after the 

 culmination 33-27o of all data; the arrivals before the culmination are 

 therefore much more numerous than afterwards. 



An elevation of 100 metres shows a delay in the arrival of the 

 Swallows of about 3 days (3-03), in departing an earlier start in the 

 higher region of about 0-7 days than in the lower ones. („Aquila" 11 pp. 

 131, 148.) 



Every geographical degree northward delays the arrival of the 

 Swallow for about M7 day. (Termeszettudomanyi Kozlony, Ann. IQOI. 

 p. 292). Temperature also sinks faster on every kilometre upwards 

 than from South to North. 



The earlier the Swallow shows its appearance in a place, the shorter 

 is the interval between the arrival and the settling for reproduction 

 (Term. Kozl. Ann. 1901. p. 294). Early comers therefore seldom 

 remain. 



Low atmospheric pressure, depression, very often shows the greatest 

 rate in the arrival of the Swallow („Aquila" VII. p. 390 and IX. 

 pag. 47). 



If there is a centre of depression west of Hungary and if its path 

 is directed to north or north-east. Swallows make their appearance 

 in crowds. („Aquila" IX. p. 48 and 68). 



The fair side of the depression, with its warm, southerly winds, is 

 therefore favourable to the arrival. 



In the same way the fair side of the depression accelerates the arri- 

 val of: Cuculus canorus, Alauda alauda, Columba oenas, Sturnus sturnus, 

 Vanellus vanellus, Motacilla alba, Scolopax rusticola, Ciconia ciconia, 

 Upupa epops, Chelidonaria urbica, Turtur turtur, Oriolus oriolus 

 Coturnix coturnix. („Aquila" iX. p. 78 and X. p. 193.) 



The other part of the depression — the bad side — with its cool, 

 northerly winds, causes delay in the arrival of the Swallow and the 

 13 species mentioned („Aquila" IX. p. 59 and X. p. 193). Generally 

 speaking, positive deviation from normal temperature has an accelera- 



aa 27 aa 4' 



