192 THE NESTS AND EGGS OF BRITISH BIRDS. 



undergo any alterations in our islands ; but in Germany 

 the bird is said to re-line the selected nest with wool 

 and feathers. I should say that in some cases, especially 

 where a Magpie's nest is chosen, the lining of roots is 

 removed. When disturbed at the nest both birds 

 become more or less demonstrative, circling above and 

 round the tree, and uttering shrill chattering cries of 

 alarm. 



Range of egg colouration and measurement : 

 The eggs of the Hobby are usually three in number, 

 but Lord Lilford records instances of four young birds 

 being taken from one nest ; so that it would appear 

 that this number is sometimes exceeded. They are 

 yellowish-white in ground colour, freckled, mottled, 

 suffused, and blotched with reddish-brown. On most 

 eggs little of the ground colour is visible, and they go 

 through every variation that is presented in the eggs of 

 the Kestrel. Average measurement, 17 inch in length, 

 by r3 inch in breadth. Incubation is said to last three 

 weeks, and to be performed by both sexes. 



Diagnostic characters: It is impossible to give 

 any character by which the eggs of the Hobby may be 

 distinguished from those of the Kestrel and the Merlin. 

 Nothing but the most careful identification at the nest 

 is of any use in authenticating them. 



