NON-INDIGENOUS BRITISH BIRDS. 115 



tree, especially in the deserted nest of a Black Wood- 

 pecker, or in the hollowed logs and the nest-boxes placed 

 for the accommodation of Ducks by the peasants. It has 

 also been known to lay its eggs on the top of a broken 

 pine trunk, in which a female Golden-eye was sitting on 

 her nest some six feet below ; the top of a broken birch 

 stem has also been selected. In America, the Hawk 

 Owl is stated by Macfarlane to build a nest of sticks, 

 and the observation is confirmed by later observers. 

 Mr. Raine, in his interesting work on Bird-nesting in 

 North-west Canada^ gives the date and locality of at 

 least three nests, two of which were made of "sticks and 

 leaves," and one of them lined with grass and feathers. 

 Further information is much to be desired, as it seems 

 probable that the nests were those of some other birds 

 which the Owls had appropriated. These birds are very 

 pugnacious when disturbed at the nest. The eggs appear 

 often to be laid at intervals, and to be incubated at once. 



Range of egg colouration and measurement : 

 The eggs of the Hawk Owl are from five to eight in 

 number, smooth in grain, with some polish, and pure 

 white. Average measurement i"55 inch in length by 

 1*2 inch in breadth. Incubation is performed by both 

 sexes, but the duration of the period is apparently 

 unknown. 



Diagnostic characters: The eggs of the Hawk 

 Owl unfortunately cannot be distinguished from those of 

 the Long-eared Owl and the Short-eared Owl, so that 

 they require the most careful identification to render 

 them of any scientific value. 



