BIRDS UNDER WATER 155 



general rule, cormorants also seem to come up 

 to swallow their fish, but a shag and a small 

 African cormorant they had at the Zoo used 

 to swallow under water like penguins, and 

 one common cormorant did so too, so perhaps 

 this is a trick that some clever birds learn, 

 and the others do not. 



So far all the divers I have been speaking 

 about belong to families of birds all of which 

 dive, except the dipper, which belongs to a 

 land-bird family ; and in some water-bird 

 families we find that some are regular divers 

 and others only surface-swimmers. This is 

 so with ducks ; every one has seen how 

 ordinary ducks, though they dive for fun, 

 only turn " end up " when it is a case of 

 feeding under water, and so cannot reach the 

 bottom through more than a foot or so of 

 water ; but there are regular diving ducks, 

 like the tufted duck and red-headed pochard, 

 which always go down for their food. Tufted 

 ducks are very easy to watch in St. James's 

 Park, where you can see them travel about 

 over the bottom, looking for the shell -fish 

 on which they feed so much, and can notice 

 several interesting things about their move- 



