SUSSEX CROSSBILLS 41 



the point of the upper mandible distinctly hooked, 

 the hook, however, having a straight-cut face, not 

 a curved one ; and the upper mandible is brownish- 

 grey with a tinge of green about it, fading into 

 yellow along its edges, the lower one greenish- 

 grey and paler altogether, also fading into yellow 

 along the line where the two mandibles meet. 

 The interior of the mouth is an intense shade of 

 carmine, the tongue crimson. The irides are 

 dark hazel. From ten days to a fortnight after 

 leaving the nest the young begin to acquire the 

 crossed mandibles which do not always cross 

 from the same side and take a week exactly to 

 obtain this doubtful ornamentation. Just at this 

 period the base of the mandibles is very loose, 

 and the little fellows probably to help on the 

 ' twist ' ' now especially love to lay hold of and 

 tweak viciously any conveniently sized twig or 

 piece of wood. Moreover, I have seen Crossbills 

 young and old aid their progression amongst 

 the branchlets by the use of their bill, as is a habit 

 of young Herons and Long-eared Owls. 



Return must now be made to the promising 

 quartet. It was noticeable that their parents never 

 came near the nest as we were examining it, nor 

 did we hear them calling anywhere traits I have 

 noticed with some other pairs with young ; though 

 nearly always over eggs, and even with regard to 

 an unfinished nest, the birds are excessively 

 agitated, and, withal, extremely tame. For 



