XVIII 



observations, but of an observation-network 

 wiiich shall cover the whole of England as 

 closely as possible. 



I have no intention of depreciating Eagle- 

 Clarke's work ; on the contrary his work is 

 most praiseworthy and of particular value 

 for his correct apjilication of meteorological 

 elements. T\u' starting-point of his work is 

 invaluable, and certain German ornithophilo- 

 sophers in Germany would do well to take 

 it to heart. Eagle-Clark says that the object 

 of the English observations was to procure 

 the most perfect and reliable data possible 

 concerning the birds passing England's coasts, 

 not the discovery of the cause of the pheno- 

 menon, still less the evolution of the migra- 

 tory instinct or the setting uj) of other theo- 

 retical theses. That is quite iu Bacon's style 

 and correct. 



Of great value is the proof that the passage 

 over Heligoland and that on the east coast 

 of England derive from ditferent sources, 

 seeing that the chief nu)menta of the two 

 passages are very rarely similar. 



I have myself in Aquila declared and 

 proved that there is a close connexion 

 between migration and the weather.* That 

 the autumn ndgration begins at a time of 

 high atmospheric ])ressure (anticyclone) has 

 been proved by Hkgyi'uky (Aquila. Tom II. 

 1895. pp. 145 — 149.) and by Punqur in his 

 great work on the chimney-swallow (Aquila. 

 Tom XL 1904.).** That normal weather implies 

 normal migration is a fact which we too have 

 experienced and given utterance to. The state- 

 ment of Eaole-Clarke that bad weather hastens 

 migration is dis|u-oved by the observations 

 made by us, wliich have established that 

 migration is hmdcred by bad weather, though 

 the tiight becomes visible, as has been poin- 

 ted out several times in Aquila.*** 



These are, practically speaking, the only 

 elements of comparison between insular Eng- 

 land and • continental Hungary. 



As far as the progress of the migration is 

 concerned, and in respect of the process of 

 settling, no detinite conclusion can be arrived 

 at except by a mutual comparison of the 

 elaborations of the ivhole material : such has 

 not as yet been ofl'ered by England, but we 

 hope will be forthcoming before long. 



Tlui „Ibis" may ask, why I did not make 

 these remarks in the publications prepared 

 for the IV^'' International Ornithological Con- 

 gress in London (1905) ? The reason is a 

 very sini|)l(' one: all of us who are interested 

 in ornithopliaenology were convinced that we 

 should have an opportunity of welcoming, at 

 the Congress, a voluminous elaboration of 

 the rich English material, an expectation that 

 was justitied by the concluding words of the 

 above-mentioned work of Eagle-Clarke. Had 

 our exjiectations been fuliilled, the said re- 

 marks would have been simply superfluous. 



Finally I \v(mld rcmiark that the Danish as 

 well as the »Saxon works are merely data 

 (nuiterials), not elaborations (digests). Yet the 

 latter are the essential part, for without them 

 it will be impossible to make a comparison 

 of the phenomena of the respective districts. 



The „Ibis" must certainly admit that the 

 l)rolileni of ndgration cannot be solved from 

 the standpoint and on the basis of observa- 

 tions, however exact they may be, made in 

 one single country, whether that country be 

 England or Hungary; that the solution depends 

 on a knowledge of the conditions of the whole 

 territory covered by the phenomenon ; that, 

 just as individual years are, meteorologically, 

 uneipial, the migration, which is so essentially 

 dependent on the weather, shows moditications 

 yearly ; that we nuist be acquainted with all 



* Der Friihliiif^szug der Rauchschwalbe — Hirundo 

 rustica L. Aquila I. p. 9. 



"■ Theoretische Bestiiniiiuug des liauchschwalben- 

 zuges und der gleichzeitigen Lufttemperatur ; and : 

 Das Wetter zur Zeit des massenhaften Wegzuges der 

 Rauchschwalbe im Jahre 18i)8. 



•"TitüsCsökgey: „Fünf Monate in Spalato' : Aquila 

 X. 71: „the weather from the middle of March till 

 the end of April was almost without a break favou- 

 rable; sunny days, with a light wind or none at all, 

 — the ideal conditions for the migratory flocks to fly 

 over Spalato undisturbed. For weeks the whole country 



seemed to be without life. At last came the 28'h 

 of April. The night before there had been a terrific 

 thuiuierstorm, accompanied by a torrent of rain: and 

 in tlu' morning all bushes, all rocks were ahve with 

 birds hindered in their flight. Dull weather continued 

 next day too. Still tired flocks of swallows and fly- 

 catchers arrived from the direction of the stormy 

 sea. On the 30"'. the sky cleared and the environs 

 of the town seemed quite void of Ufe again, as even 

 the day-wanderers were flying quite out of roach of 

 mortal eyes". 



