Birds. 6541 



" 1. That the swarm of insects is spheroid, which it will constantly 

 tend to be for the reasons before given. 



" 2. That the mean of the divergences of the bird's flight equals a 

 tolerably straight line, which we may observe it very often does, 

 because, as has been shown, the bird's attention is directed laterally 

 as much to one side as the other. 



" 3. That in making the angle at the circumference it will be such 

 that he shall keep nearest the middle and densest portion of the 

 swarm, but furthest from his own previous course. 

 , "Then it is mathematically certain his flight will be in triangles, as 

 your observant coadjutor Mr. Hill long ago remarked. It is quite im- 

 possible for us to devise a plan by which, with less loss of time, he 

 could keep so constantly near the middle and distant from his pre- 

 vious flight. I need hardly add that the triangle is by no means 

 always equilateral, as, for the sake of clearness, I have given it. 



" I have never been able to ascertain anything respecting the diuraal 

 repose of these birds; but large cotton trees have been pointed out, 

 whence, the neighbours assured me, the piramidigs were seen to issue 

 every evening. The universal negro answer is, * Him no go in tree and 

 lie down, like a galliwasp ? ' This would not be of much value were it 

 not for your observation of this habit.* It seems to me that this is 

 really the normal mode of repose, not only if we consider its efficacy, 

 but from tlie peculiar formation of the foot, which, as is well known, 

 has the short hallux placed very laterally. In the short-winged 

 Caprimulgus I have met with, the tarsus-joint is also worn as if it were 

 constantly rested on. 



" Very faithfully yours, 



" W. OSBURN. 

 " To p. H. Gosse, Esq." 



A List of the Birds of Banffshire^ accompanied with Anecdotes. 

 By Thomas Edward. 



(Continued from page 6672.) 



Kingfisher [Alcedo ispida). Several of these sparkling gems have 

 been taken here at different times. 



* See ' Birds of Jamaica,' p. 37. I shot a night-hawk by day, resting lengthwise on 

 a branch of a tree. See also the remarks of Mr. Bartlett on the European nightjar, in 

 the ' Zoologist' (Zool.445), " It is a constant habit of these birds to perch lengthwise, 

 with the head lowest, — that is, inwards to the tree." — P. H. G. 



XVIII. H 



