OBSERVATIONS ON BIRDS 345 



above-mentioned is occasioned by the astrus bovis, a dipterous 

 insect, which lays its eggs along the chines of kine, where the 

 maggots, when hatched, eat their way through the hide of the 

 beast into the flesh, and grow to a very large size. I have 

 just talked with a man who says he has more than once 

 stripped calves who have died of the puckeridge ; that the ail 

 or complaint lay along the chine, where the flesh was much 

 swelled and filled with purulent matter. Once I myself saw 

 a large rough maggot of this sort squeezed out of the back of 

 a cow. 



These maggots in Essex are called wornils. 



The least observation and attention would convince men 

 that these birds neither injure the goatherd nor the grazier, 

 but are perfectly harmless, and subsist alone, being night 

 birds, on night insects, such as scarab cei and phalcence ; and 

 through the month of July mostly on the scarabceus solstitialis, 

 which in many districts abounds at that season. Those that 

 we have opened have always had their craws stuffed with 

 large night moths and their eggs, and pieces of chaffers : nor 

 does it anywise appear how they can, weak and unarmed as 

 they seem, inflict any harm upon kine, unless they possess the 

 powers of animal magnetism and can affect them by fluttering 

 over them. 



A fern-owl this evening (August 2/th) showed off in a 

 very unusual and entertaining manner, by hawking round and 

 round the circumference of my great spreading oak for twenty 

 times following, keeping mostly close to the grass, but occa- 

 sionally glancing up amidst the boughs of the tree. This 

 amusing bird was then in pursuit of a brood of some particular 

 phalaena belonging to the oak, of which there are several 

 sorts ; and exhibited on the occasion a command of wing 

 superior, I think, to that of the swallow itself. 



When a person approaches the haunt of fern-owls in an 

 evening, they continue flying round the head of the obtruder ; 

 and by striking their wings together above their backs, in the 

 manner that the pigeons called smiters are known to do, make 

 a smart snap ; perhaps at that time they are jealous for their 

 young, and their noise and gesture are intended by way of 

 menace. 



