180 BRITISH BIRDS WITH THEIR NESTS AND EGGS. 



albino variety is in Mr. Marshall's collection, and an example pure white (including 

 the legs and bill), except a few dark feathers on the back, shot in Essex, is 

 mentioned in Mr. Miller Christy's work on the birds of that county. 



FAMILY PODICIPEDIM. 



THE Grebes (Podicipedidae) of which about twenty-five species are described, 

 are almost cosmopolitan in their distribution, though they do not go very 

 far towards the poles, and appear to range only as far as sub-tropical regions in 

 the other direction. The Grebes have their bodies thickly covered with peculiarly 

 soft and silky feathers. Their tarsi are narrow and knife-edged; the feet (four- 

 toed) are not webbed, but the toes are flattened out and widened with broad 

 lobes ; this is the most remarkable feature in their external structure. In these 

 birds the tail is virtually absent, and the body short and flattened laterally ; the 

 wings are short. 



The sexes are practically alike in plumage, but the seasonal changes of 

 plumage are very great, the most remarkable part of which consist in the assump- 

 tion of ornaments (ruffs and frills) on the head, by most of the species, in the 

 breeding season. 



Grebes are migratory for the most part. They breed on fresh water lakes 

 and rivers, and to some extent are marine in their habits during winter. 



The nest is bulky and close to or floating on the water, and the eggs are 

 nearly white, unmarked, usually coated with chalky substance, and vary in number 

 from three or four up to six or eight in number. The young are hatched, covered 

 with down, and are able to take to the water almost at once. 



