INTRODUCTION. 21 
the British Isles form part of a family of about thirty species— 
a group spread over the world, mainly in the temperate regions 
of both Hemispheres. 
Still more aquatic in their habits, and perfect in their diving 
movements, are the half-dozen or so of Divers, par excellence, 
whereof our Great Northern Diver (Colymbus glacialis) may 
serve as an example. It is a large bird, which breeds in the 


tN 
at 

The Common Guillemot ( Uria troile). 
north of North America, and visits the coasts of England and 
Scotland in the winter. The Divers live chiefly in the sea, 
feeding on moderate-sized fishes, which they catch while under 
water. They all inhabit high latitudes. 
Another much commoner but very interesting bird is the 
Common Guillemot (Uria troile). Extremely maritime in its 
