COMMON CROSSBILL. 25 



before she slips off her nest. Mr. Norgate remarks of 

 a nest taken by him in Norfolk five years ago : " On 

 March 26th I took a nest of four Crossbills' eggs from a 

 Scotch fir ; the hen bird objected to leave the nest even 

 after it was brought down from the tree, when three or 

 four other Crossbills came and fluttered about close to 

 our heads, uttering their peculiar cry and showing their 

 hooked beaks." When disturbed from her eggs the 

 female is often joined by the male, both birds fluttering 

 about in an anxious, restless manner. 



RANGE OF EGG COLOURATION AND MEASUREMENT : 

 The eggs- of the Crossbill are usually four in number, 

 occasionally three, more exceptionally five. They vary 

 from white to white tinged with green in ground colour, 

 spotted with reddish-brown, and with underlying mark- 

 ings of paler brown. The spots, never very large, are 

 mostly distributed over the larger end of the egg, where 

 they not unfrequently form an irregular zone. Many of 

 the spots often take the form of streaks, and then the 

 colour is exceptionally dark. Average measurement, 

 9 inch in length, by 7 inch in breadth. Incubation, 

 performed by the female, lasts fourteen days. 



DIAGNOSTIC CHARACTERS : It is impossible to give 

 any absolutely reliable character by which the eggs of 

 the Crossbill may be distinguished from those of the 

 Greenfinch. The range of colouration is practically the 

 same in each species, but as a rule the eggs of the latter 

 bird are smaller. The date of laying is one reliable 

 characteristic, the Crossbill producing eggs as a rule 

 from one to two months earlier than the Greenfinch. 



