SEASONAL CHANGES OF PLUMAGE IN BIRDS. 221 
one finds that many of the white feathers of winter are still 
visible, giving the bird a checkered appearance. 
What appears most strange is that these birds never reach 
what is considered the typically adult summer plumage of the 
Golden Plover. It matters not at what period of the breeding 
season, this undeveloped plumage is always conspicuous. Now, 
I would ask, what is the natural cause of this ? 
Even in Shetland the summer dress of the Golden Plover is 
much darker, i.e., more developed than in Northumberland ; but 
if we visit Lapland or Siberia, we find there the Golden Plover in 
what we consider their typically adult summer dress. If they 
had to endure greater cold or stress of weather at their northern 
breeding-stations, one could perhaps account for the more adult 
form of plumage by a greater thickness of feathers; but such is 
not the case. Indeed, I venture to say that the Northumberland 
birds have, if anything, the greater cold to endure. Perhaps it is 
that the birds which frequent our moors in winter are not the 
birds which remain to breed with us; possibly all these birds 
migrate northwards to Lapland and Siberia, their places being 
taken by another and different set of birds, which have spent 
their winter in more southerly latitudes, and which make our 
counties the northern limit for their spring migration. This is a 
theory difficult to solve. It may be that the reverse is the case, 
and that the birds which winter also remain to breed with us, 
and that there is a great migration from the Mediterranean 
direct to the morasses and tundras of Siberia. 
I think, perhaps, this is most likely to be the case, as many 
specimens of birds which seldom breed south of the Arctic circle 
are regularly obtained in their adult summer plumage in the very 
south of Europe, about the middle of May. 
My brother, Mr, Abel Chapman, shot Curlew Sandpipers 
(Tringa subarquata) in their rich rufous plumage, as well as Grey 
Plovers (Charadrius helvetica) in adult summer dress, on the 
Guadelete, near Jerez, in Southern Spain, on May 8th, and these 
birds would have about 3000 miles to travel northwards before 
they could find a suitable breeding-ground; although perhaps it 
is not necessary to mention here that the Curlew Sandpiper is, I 
believe, the only British bird whose nest has never yet been 
discovered. The rapidity with which birds execute their spring 
and autumn migrations must be something marvellous, for I have 
