COURTSHIP OF DUCKS AND NOTES ON HYBRIDS. 695 
throws his head backwards and forwards as well as up and 
down, at the same time uttering his well-known crackling note. 
This species and the Shoveler have another habit in common — 
that of swimming in circles round and round, the bills of both 
male and female being partly submerged in the water just 
behind and below the tail of the other. I have never been 
able to satisfy myself that this is actually courtship or merely 
a ruse to stir up insect life below the surface, but it is 
significant that it is only performed during the spring of the 
year. 
In the case of the common Wigeon, early in the season 
several males clamour round one female ; there may be other 
females in the vicinity apparently not ready to receive the 
attentions of the males, and these swim about by themselves, 
taking no interest in the fuss going on round them. The 
excited males round the female lower their heads along the 
surface of the water and whistle repeatedly, this whistle 
resembling the word whee-ou ; the yellow feathers of the fore- 
head are raised and the feathers of the head puffed out, at the 
same time the males raise their beautiful long black-and-white 
scapular feathers. 
All adult British surface-feeding ducks appear to commence 
displaying in October, directly their winter plumage is com- 
plete ; but I have seen Mallards display in full eclipse plumage. 
Mallards of the year commence about the same time, even 
before they have attained the full winter dress. I have seen 
immature Garganev drakes displaying when only just beginning 
to assume their adult plumage ; but this is not surprising if 
one bears in mind the age of the bird, since immature 
Garganeys do not attain full breeding dress until months after 
Mallards of the same age. Further, with the exception of 
individual Shovelers, adult Garganeys are much longer in 
eclipse plumage than are any other surface-feeding ducks. 
This disposes of all the British Surface-feeding ducks, and 
we will now take the family of Diving-ducks. With these 
there seems to be one action common to all of them while in 
