2oo ALLEN'S NATURALIST'S LIBRARY. 



slightly larger form, Z. holboelli, which ranges from Greenland 

 westwards, and occurs in Eastern Siberia, varying south in 

 winter to Japan and even reaching Turkestan, according to 

 Severtzoff. This form is very doubtfully distinct from Z. 

 griseigena. It has a wing of 7 '2-8*2 inches, whereas the wing 

 of Z. griseigena varies from 6*0-7*3 inches ; thus it will be seen 

 that the dimensions of the wing in these two forms overlap. 



Habits. Seebohm, who had opportunities of studying this 

 species in its native habits, writes : " In North Germany it is 

 a very common bird, arriving late in March or early in April, 

 and leaving again in October. It is almost exclusively an in- 

 habitant of lakes and ponds, where sedge or reeds abound. 

 On small ponds solitary pairs are found, but on the larger 

 lakes great numbers breed together, though the nests are 

 scattered up and down amongst the reeds, and not clustered 

 together in a colony. The nests are sometimes placed in the 

 recesses of the thick reed-beds, but quite as often they can be 

 seen at a considerable distance in localities where the reeds are 

 only half-grown and thinly sprinkled over the water. The nest 

 is always floating, so that it can rise or fall with the water, and 

 is considerably less than that of the Coot. It is somewhat 

 carelessly made of reeds and decayed water-plants, and near 

 each nest is a sort of sham nest, or foundation of a nest, 

 merely a few reeds laid together, which is used as a roosting- 

 place for the parent which, for the time being, is not occupied 

 with the incubation of the eggs. Fresh eggs may be obtained 

 during the first half of May. When the third egg is laid the 

 bird begins to sit ; but it is ever on the look-out for danger, 

 and long before the nest can be discovered, the approach of an 

 intruder has been observed, the eggs have been carefully 

 covered with black weeds to keep them warm, and the b ire- 

 may be seen apparently feeding at a distance, looking as inno- 

 cent and unconscious as possible." 



Nest. Made, like those of other Grebes, of reeds and de- 

 cayed water-plants. 



Eggs. Three or four in number. Greenish- white, covered 

 with a chalky substance when fresh, but becoming discoloured 

 to a buff or brown shade. Axis 1*85-2*15 inches, diameter 

 t'3-1'4- 



