BIRDS. 
335 
whence it is called Caprimulgus, and with us, of communi- 
cating a deadly disorder to cattle. But the truth of the 
matter is, the malady above-mentioned is occasioned by the 
CEstriis hovis, 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 wormils. 
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 Scarabcei, and Phalcence; 
and through the month of July mostly on the Scarahceus 
solstitialis, which in many districts abounds at that season. 
Those that we have opened have always had their craws 
stufied with large night moths and their eggs, and pieces of 
chafers : 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 afiect them by fluttering over them. 
.A fern-owl, this evening (August 27), showed oflP in 
a very unusual and entertaining manner, by hawking 
round and round the circumference of my great spread- 
ing oak for twenty times following, keeping mostly close to 
the grass, but occasionally glancing up amidst the boughs 
of the tree. This amusing bird was then in pursuit of a 
brood of some particular Phalcena 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 siniters arc known to 
