THE BIRD-LIFE OF LONDON 
frequent visitor to Wanstead and other suitable parts of 
the Essex suburbs. 
That Terns of several species visit the Metropolitan 
area during their annual migrations has long been known. 
It is impossible to name the exact species in a great many 
instances, observations, unless made by an expert or a 
person familiar with the various Terns that frequent the 
British seas during summer, being practically worthless 
in this respect. Both the Arctic Tern (Sterna arctica) 
and the Common Tern (Sterna hirundo), there can be no 
doubt, occur casually within our limits not only in the 
vicinity of the river, but elsewhere at reservoirs and other 
large sheets of water. ‘Their visits, however, are always 
fleeting ones, merely incidents of the migration journey 
the birds are engaged upon, and of transient interest 
only to the London observer. The Sandwich Tern 
(Sterna cantiaca), the largest of the species that visit the 
British Islands, has also, I believe, been recorded from 
the Metropolitan area. Lastly, allusion may be made to 
the Black Tern (Hydrochelidon nigra), which evidently 
passes London’s environs on migration at times. It has 
also been observed north of our limits at Tring Reservoirs, 
from which we may reasonably presume that Kingsbury, 
the Welsh Harp, and other lakes in that direction are 
visited too. 
298 
