240 ; THE ZOOLOGIST. 
EXPLANATION OF PLATE. 
Fic. 1. Fratercula arctica, adult male, in spring, or during the breeding 
season (natural size). Coast of Brittany, 6th June, 1876. (Coll. 
Dr. Bureau.) 
Fie. 2. Fratercula arctica, adult male, in winter or after the breeding 
season (natural size). Cape Ferret, near Arcachon, Gironde, 
4th March, 1873. (Coll. Dr. Marmottan.) 
Fic. 8. Fratercula arctica, undergoing the moult (enlarged to twice the 
natural size). 
Fic. 4. Fratercula arctica. Adult assuming the nuptial appendages. 
Fic. 5. Horny pieces which fall off after the breeding season. 
BIRD MIGRATION IN THE SPRING OF 1878. 
By Joun CorDEAUx. 
TuE following notes, although perhaps not containing anything 
of special importance, will be interesting to British ornithologists, 
showing as they do the almost continual stream of migrants 
which passed Heligoland for many weeks in succession during 
the spring of the year. They were sent to me from time to time 
by that indefatigable observer, Mr. Gitke, and are taken from 
his own notes and observations. 
The autumn migration of birds southwards in 1877 was greatly 
prolonged beyond the usual period ; and from Mr. Gatke’s notes it 
appears that, even as late as the commencement of February, 
all the birds had not left the North of Europe, many laggards 
remaining after the usual period of migration. This abnormal 
state of affairs was probably induced by the extremely mild winter 
of 1877-78 in Scandinavia. Food continuing accessible, and the 
weather being not too severe, some of the more hardy species seem 
to have delayed their journey southward until the early part of 1878, 
when the sudden outburst of severe weather towards the end of 
January sent the loiterers southward with a rush. It will be seen 
that scarcely had the down-stream ceased, before the return flood 
set in, and continued, with but slight intermissions of unfavourable 
EE 
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