EXCEPTIONAL MIGRATION PHENOMENA 117 



Larks. And again, in the night of the 11th of October 1883, during 

 which an unusually strong migration of all the sjiecies of birds due 

 at that time took place, this was accompanied by the appearance 

 of very large swarms of the same species of Hybernia. 



White Cabbage Butterflies,tho Black Arches, Psihira vionacka, 

 and also Libellulidiv, LUidlula quadfipuvctata, have been seen 

 to pass here in migratory flights of astonishing proportions, though 

 even these do not come ujj to those of Plusia gamina, which on 

 repeated occasions have occurred in numbers of which it would 

 be quite impossible to form any conception. Thus, during the 

 nights from the 15th to the 19th of August, under the favour- 

 able conditions of a south-easterly wind and fair weather, a con- 

 siderable migration of birds took place. On each of these nights, 

 from 11 P.M. to 3 a.m., the small Noctuje above referred to 

 were seen at the lighthouse, passing from east to west in undi- 

 minishing numbers, like the flakes of a dense snowstorm. These 

 , small creatures also manage to cross the North Sea in safety, for 

 they often arrive on the east coast of England suddenly, and in 

 such remarkable numbers, that we can only believe them to be 

 immigrants. In fact, as my friend John Cordeaux informs me, an 

 enormous accumulation of these insects actually took place at a 

 time corresponding to that of tlie above observations. 



Returning, however, to the subject of the present chapter ; it is 

 the residents of the far east of Asia which, if not in the number of 

 species, yet at any rate in that of individuals, must claim our first 

 attention. Even if the Richard's Pipit can no longer be regarded 

 among the rare occurrences of Heligoland, this still applies to the 

 Yellow-browed Warbler and the Little Bunting, of each of which 

 species some thirty freshly-killed specimens have passed through 

 my hands, whilst at least double that number has been observed 

 here within the last forty years. AVhite's Thrush I have obtained 

 on five occasions ; this splendid thrush having, before my time, 

 come five or six times into the hands of Brand of Hamburg. The 

 Rustic Bunting I have obtained nine times, and the Yellow-breasted 

 Bunting (E. aureola) three times. Besides these, the following birds 

 have been killed here in one or two instances : — The Red-throated 

 Thrush (Turdus ruficollis), the Black-throated Thrush (T. atri- 

 gidaris), and the Dusky Siberian Thrush (T.fuscatus): the Siberian 

 Chiffchaff {Sylvia tristis), Dusky Willow- Warbler {S. fuscata), 

 S. viridana, S. borecdis, S. nitida, S. coronata, S. proregidus, 

 Booted Wai-bler {S. salicaria), and Pallas' Warbler (S. certliiola) ; 

 also Pyrrlnda rosea, Cinchis pallasi. To these may, 2>erhaps, be 

 added one or two other species of those already mentioned ; Sylvia 

 viridana has actually been killed on three occasions. 



