168 



On the Ornithology of Wilts. 



are furnished with very broad and much depressed mandibles ; all 

 are peculiarly formed for holding securely their food, which is 

 frequently of a slimy and slippery nature. 



We have now run rapidly through the several orders and tribes, 

 paying attention to the general formation of the beak in each, and 

 have seen how strong a resemblance usually pervades all the fami- 

 lies contained in them : we cannot fail to have observed at the 

 same time how admirable in every case was the construction for 

 attaining the desired end. There are still some particular species, 

 which exhibit so remarkable a peculiarity in this organ that I am 

 unwilling to pass them by. 



One of the most curious is the Crossbill, a bird familiar to most 

 persons, as it occasionally though not periodically visits us in con- 

 siderable numbers ; its name at once points out what some persons 

 (and those naturalists of eminence, including the zealous but often 

 inaccurate Buffon) have been pleased to call its natural defect, but 

 which is now pretty generally considered a most admirable pro- 

 vision of nature : these birds inhabit extensive forests of pines and 

 firs, the seeds of which form their chief food, but to arrive at these 

 a peculiar instrument is necessary. To this end the mandibles 

 (which in young birds in the nest are of the ordinary form) become 

 elongated and cross one another at the tip to a considerable degree : 

 in some specimens the upper mandible is curved to the right, the 

 lower to the left ; in others this order is reversed ; in either case, 

 by means of these beaks, and by the lateral motion of the mandibles 

 (which is peculiar to the crossbills alone of all birds), they are 

 enabled by insinuating the points between the scales of the pine 

 cones, and by the powerful lever they possess in their singular bill, 

 to wrench open the scales without difficulty, and so obtain the fruit. 

 With this strange instrument they are no less adept at splitting 

 apples and pears for the sake of the enclosed pips. It may readily 

 be conceived that to work so strong a bill, the muscles attached 

 to it must also be of proportionate power and size, and these are 

 the cause of the large, heavy, and somewhat awkward appearance 

 which the head presents. 



Another bird remarkable for its peculiar beak is the Avocet; this 



