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work tlieir way across the country to the east coast : here they 
assemble in greater or less numbers according to the state of wind 
and weather, waiting for a favourable opportunity to cross the North 
Sea. It is the left wing, if I may use the expression, of the stone- 
chats which at this season sweeps across Heligoland, and thence in 
an E.S.E. direction across Europe to their winter quarters in lands 
surrounding the north-east shores of the Mediterranean. 
In the same manner, in the spring, it is the extreme right wing 
which touches Heligoland on their way to the eastern shores of 
England and Scotland ; that is, in the autumn our English birds 
cross directly to the coast of Holland and Belgium from Norfolk 
and Lincolnshire, and return in the spring by the same route. 
Instances, as we could name, are not uncommon amongst birds 
of the Western Palsearctic regions, of a migration at variance with 
the usual line of migratory flight. Perhaps one of the most 
noticeable is that of the yellow-crowned warbler, Phylloscopus 
superciliosus. That individual, of a small and delicate willow 
wren, whose nesting haunts are in the warm sheltered mountain 
valleys of Southern Siberia, Turkestan, and Cashmere, and its 
winter quarters in Southern India and China, Pegu, and the 
islands of the Pacific, should regularly in the autumn appear in a 
distant spot of Western Europe, is confessedly one of the most 
puzzling anomalies of migration. From some cause or other, these 
small wanderers take their flight exactly in an opposite direction 
to the rest of their species; N.W. into the cold and gloomy north, 
instead of S.E. to the eternal summer of the tropics. They cross 
much of Asia, all Europe, and then continuing their flight over 
seventy miles of sea, alight for a time on a bleak red sand-stone 
rock, affording little or no shelter. That they should turn up in 
Heligoland more than in any other locality along their route is 
doubtless due to the very circumscribed area of the island, as well 
as the close look out for rare wanderers kept by the indefatigable 
ornithologist and his assistants living on that'bleak spot. 
