326 THE NESTS AND EGGS OF BRITISH BIRDS. 



certain chosen spots. The nest is invariably placed on 

 the ground, the bird choosing an island wherever a 

 preference can be exercised ; but frequently the bank of 

 a mountain pool is selected. If the nest is made on 

 shingle or bare ground it is more elaborate than when 

 on grass or amongst vegetation. Even the most elabor- 

 ate nests are little more than hollows sparsely lined with 

 a little dry grass or fragments of more aquatic herbage. 

 The nest is seldom far from the water-side. The bird 

 does not sit very closely, usually gliding off the nest 

 and shuffling into the water the moment it is alarmed. 

 Neither is it a demonstrative bird, but it sometimes flies 

 over the intruder in its anxiety to learn the fate of its 

 home. 



Range of egg colouration and measurement : 

 The eersfs of the Red-throated Diver are two in number, 

 narrow and elongated in form. They vary from 

 brownish-olive to pale buffish-brown in ground colour, 

 spotted and speckled with very dark brown, many of 

 them almost black, and with a few indistinct underlying 

 markings of paler brown. The spots vary from about 

 the size of a pea downwards. But little variation is 

 seen in the eggs of this species. Average measure- 

 ment, 2'8 inches in length, by r8 inch in breadth. 

 Incubation, performed chiefly if not entirely by the 

 female, lasts, it is said, about a month. 



Diagnostic characters : The elongated form and 

 dark decided spots characterize the eggs of this and the 

 following species (the only two known to breed In our 

 area), and the small size is the distinguishing feature of 

 those of the present bird. Unfortunately, however, the 

 egg measurements of these two Divers overlap in rare 

 instances, so that it behoves the collector thoroughly to 

 identify his specimens. 



