NON-INDIGENOUS BRITISH BIRDS. 3 



tree at from fifteen to thirty feet from the ground. The 

 nest is made on one of the nearly horizontal branches 

 close to the trunk, and is a bulky open structure com- 

 posed of larch, fir, and birch twigs, often cemented with 

 a little mud or clay, and lined with moss, roots, strips of 

 bark, and grass either dry or semi-green. The Nut- 

 cracker makes little or no demonstration when disturbed 

 at the nest, slipping away very quietly ; the female 

 usually sits remarkably close, remaining brooding over 

 her eggs until she is almost touched by the hand, 

 or the stem of the tree is smartly knocked. 



Range of egg colouration and measurement : 

 The eggs of the Nutcracker are from three to five in 

 number, but three appears to be the average clutch, and 

 occasionally only two. They range from very pale 

 greenish-blue to creamy-white in ground colour, freckled 

 and spotted over the entire surface with olive-brown and 

 underlying markings of pale gray. Very exceptionally 

 a fine hair-like streak of darker brown occurs. The 

 amount of marking varies considerably, and on some 

 specimens most of the spots are on the larger half of the 

 ^g§ j o" some varieties the pale gray underlying mark- 

 ings predominate and the surface spots are few and 

 large. Average measurement, v^ inch in length, by "95 

 inch in breadth. Incubation, performed by the female, 

 is presumed to last from sixteen to eighteen days. 



Diagnostic characters : The eggs of the Nut- 

 cracker so closely resemble the paler varieties of those 

 of the Magpie that they cannot with absolute certainty 

 be distinguished. Under a microscope the shell of the 

 Nutcracker's ^^g is of much finer grain than that of the 

 Jackdaw, another species with which it may be confused ; 

 it is also more fragile and the spots are never so intense. 

 The site and description of the nest prevents any chance 

 of confusion in the field. 



