8o THE NESTS AND EGGS OF 



underwood in pine and juniper forests, and the willow 

 scrub and hummocky portions of the open Arctic tundra. 

 The male is very remarkable for his varied and melodious 

 song, often uttered whilst he hovers Pipit-like in the air, 

 which arrests the attention at once the moment his 

 haunts are reached. Of the pairing habits of this Robin 

 nothing appears to be known. It may mate annually at its 

 breeding grounds, as there is some evidence to suggest 

 that the sexes do not migrate in company. The nest of 

 this bird is made on the ground in some swampy spot 

 in the forest or in one of the endless hummocks of the 

 tundra. These mounds are a mixture of rough grass, 

 rushes, carices, ground fruits, and dwarf willows and 

 birches. The nest is very similar to that of the Robin, 

 being made on the same model, placed in a hollow, the 

 cup containing the eggs being well at the back, and the 

 frontage to the nest being broad. Externally it is made of 

 dry grass, roots, reindeer-moss, and dead leaves of various 

 Arctic plants, lined with fine roots and hair. It is so 

 cunningly concealed as to be found with the greatest 

 difficulty, and, as is usual with species nesting in such 

 spots, the bird sits closely. This species is not gregarious 

 during the breeding season, but numbers of pairs may 

 be found nesting within a small area. 



Range of egg colouration and measurement : 

 The eggs of the Arctic Blue-throated Robin are five or 

 six in number. They vary from bluish-green to pale olive 

 in ground colour, somewhat indistinctly mottled with 

 pale reddish-brown. As a rule most of the markings 

 are pretty evenly distributed, but types occur in which 

 the colouring matter is mostly in a cap or zone round 

 the larger end of the egg. Average measurement, 75 

 inch in length by "55 inch in breadth. Incubation is 

 performed chiefly if not entirely by the female, but the 

 duration of the period is unknown. 



