522 Dr. A. L. Thomson : Results of a Study of [Ibis, 
the assumption that the individuals had left the respective 
localities in the interval. There are two instances of Mallard 
being found in a totally different area in subsequent summers, 
but as all the other evidence points to the native birds of 
that species being sedentary, the explanation of these as 
exceptional cases, already suggested, seems to be justified. 
Return of Migrants to the same Winter-Quarters. —The only 
definite evidence on this point rests on a single record and 
refers to the Herring-Gull, a species which can scarcely be 
regarded as a typical migrant. 
Winter-Quarters of Native British Birds. —The records for 
a number of the species dealt with indicate, at least in part, 
the winter-quarters of individuals which are summer visitors 
either to the British Isles as a whole or to particular districts 
therein. The small chances of obtaining records from, say, 
northern Africa make it impossible to regard these indica¬ 
tions as exhaustive. 
Summer-Quarters of Winter Visitors to the British Isles .— 
The only very definite evidence under this heading refers to 
the Starling ( q. v.). 
Part taken in Movements by Native British Birds. —As has 
already been repeatedly pointed out, it is typical of migration 
in the British area, which is a “ half-way house ” in Tem¬ 
perate Europe, that species should be present throughout 
the year, although known in autumn both as immigrants 
from the north and east and as emigrants to the south, and 
vice versa in spring. Some light has been thrown on the 
part played in these movements by the native British birds 
of several species. More evidence is still required, but in 
the cases of the Mallard and the Starling there is already a 
strong presumption that the native birds are sedentary and 
that any southward emigration which is observable must 
therefore be on the part of birds that have already come 
from more northerly or easterly summer areas. In other 
cases, such as those of the Lapwing and the Woodcock, the 
participation of the native birds is clearly proved. The 
theoretical interest of the point has already been discussed in 
the introduction. 
