Birds. 793 



used when flying, the discrepancy requires to be compensated by some means in all 

 birds, in order to enable them to perform flight with ease. Raptorial birds take a 

 horizontal position when suspended in the air, and the compensating power consists 

 in their taking a more or less erect position when at rest. Another class, including 

 the woodpeckers, wagtails, &c, take an oblique position in the air : with these the 

 compensating power consists in their cleaving and passing through the air at an angle 

 coincident with the position of the body, and performing flight by a series of curves 

 or saltations. Natatorial birds sometimes need very extended flight; they take a very 

 oblique position in the air ; they have the ribs greatly lengthened, the integuments of 

 the abdomen are long and flexible, which enables them greatly to enlarge the abdo- 

 minal portion of their body by inflating it with air ; this causes a decrease in the 

 specific gravity of that part, and raises it to a horizontal position. The compensating 

 power consists in the posterior half of the body becoming specifically lighter, while 

 the specific gravity of the anterior half remains unaltered. 



This paper was illustrated by the skeletons of several birds. 



Mr. A. Strickland, observing the guillemot upon the table, stated, that, although 

 this bird had the power of flying over the sea, it could not over the land. — Mr. H. E. 

 Strickland had, originally, doubted this fact, but, from experiments he had made on 

 the east coast of Yorkshire, he could confirm the statement of Mr. A. Strickland. 

 He believed this fact had never been noticed by ornithologists. — Mr. R. Ball, of 

 Dublin, stated that he had appended a note, to the effect that the guillemot could not 

 fly on land, in a paper which had been published about eight days, by the Irish 

 Archaeological Society. 



Note on the Honey Buzzard. I beg to send you notice of a Honey Buzzard (fig. 7), 

 killed near Yarmouth, towards the end of last month. It appears to form a link 



§P> 



between Nos. 1 and 2 of those figured at page 375 of « The Zoologist.' The predo- 

 minating colour of this bird is a light brown, rather darker on the back. The feathers 



ii 2 M 



