87 



On the 21st and 22nd of March 1880, the wind was east, the air 

 calm and clear ; but again hoar-frost, consequently, in the way of 

 birds, ' nothing at all.' On the 23rd : wind south-east, calm, clear, 

 hoar-frost, and nothing except a few Hooded Crows and some 

 species of Finches. On the 24th : wind south-east ; during the fore- 

 noon and later, Hooded Crows, Rooks, and Jackdaws, Wood Pigeons, 

 a pair of Wagtails and Yellow Buntings. During all these days, 

 neither Blackbirds nor Snipe were observed, although the weather 

 was such that both species would have been numerously represented 

 if this had not been prevented by the hoar-frost. On the 26th, 

 27th, and 28th : an easterly wind ; cold fog ; naturally nothing in 

 the way of birds. On the 29th : weather perfectly calm, overcast, 

 warmer ; forthwith, in the early morning hours, Starlings in flocks 

 of hundreds ; Blackbirds and Redbreasts in fairly large quantities. 

 Of Woodcocks, two hundred and fifty were killed, an unprece- 

 dented number for the spring migration. Glaus Aeuckens and his 

 nephew shot thirty-five of these birds, during the early morning 

 hours, at the foot of the cliff'. 



We have just intimated that the movements of nocturnal 

 butterflies and moths are likewise subject to meteorological in- 

 fluences; this view is supported by repeated observations, which 

 shoAV that these insects travel past this island under the same con- 

 ditions as birds, and for the most part, in their company, in an east- 

 to-west direction. They fly in swarms the numbers of which defy all 

 attempts at computation, and can only be expressed by millions. 

 Unfortunately, I have hitherto not been able to ascertain the time of 

 arrival of these multitudes of western emigrants on the English 

 coast, which might have enabled me to determine the velocity of 

 their flight in the same way as was done in the case of the Hooded 

 Crows. According to information received from my friend, John 

 Cordeaux, whose country seat is situated on the east coast of Eng- 

 land, opposite Heligoland, Plusia gamma is frequently seen there 

 suddenly in such enormous numbers that only the assumption of 

 an immigration en masse can explain the phenomenon. 



In evidence of what has just been stated. I may be allowed to 

 quote some notes relating to this subject from my ornithological 

 diary : On the night of the 25th of October 1872, during a very 

 powerful migration of Larks, many thousands ofHybernia defoliaria, 

 intermingled with hundreds of Hybernia aurantiaria, travelled 

 over the island. In the following year, on the night of the 29th of 

 July, the weather being warm and perfectly calm, thousands of 

 Eugonia angularia, together with hundreds of Gnophria quadra, 

 passed in the midst of a strong migration of young Golden Plovers 

 and Ringed Plovers, and of many Sandpipers. So, again, on the 



