58 ' REY. H. N. BONAR’ ON THE DECREASE 
\ 
adjusted economy of bird-life fit into quite another part of 
that mysteriously-regulated mechanism which we call the 
Balance of Nature, for want of a better term. We see that 
some birds become rare as others become plentiful. 
It is remarkable that the Crow-tribe (Corvidx) seems most 
of all to have its numbers affected by the presence of man. 
Some of the Corvide have almost been exterminated, and 
others have increased so largely as to become a plague. The 
Raven (Corvus corax), the Carrion Crow (Corvus corone), the 
Hooded Crow (Corvus cornix), the Magpie (Pica caudata), 
and the Jay (Garrulus glandarius), are shot, trapped, poisoned, 
and harried, till in many Scotch counties they are practically 
extinct. I must admit that these birds sometimes harm 
game or eggs or lambs; but surely this cannot justify their 
utter extinction. JI have seen one magpie in East Lothian, 
where thirty years ago it used to be fairly common; while 
the jay has not been noted in the county since 1882, when 
one was “obtained” on the Lammermuirs.* This is a 
digression intended to lead up to the fact of the extinction 
from the east coast of one member of this family, the 
Chough (Pyrrhocorax graclus). Now, this bird has never 
been abundant, and has (so far as is known) no bad _ habits, 
as its relatives have. It has not been trapped or poisoned 
or shot out. In fact, man did not systematically begin to 
persecute it till its skin or eggs became rare enough to have 
a commercial or scientific value. Its great decrease is prob- 
ably due to the abnormal increase of its impudent relative, 
the jackdaw. Yarrell suggests this.t Muirhead, in his 
Birds of Berwickshire, does so also.{ Another voluminous 
ornithological writer asserts it plainly.{ “The stronger 
daw,” he says, “is ousting the chough from its ancestral 
homes,” Professor A. Newton—always reliable—says|| that 
the jackdaw “seems to be dispossessing it of its sea-girt 
strongholds, and its present scarcity is probably, in the main, 
due to its persecution by its kindred.” 
But the jackdaw has another serious charge made against 
him—that of driving out the Barn Owl (Stria flammea) 
* Annals Scot. Nat. Hist., Jan. 1898. + Brit. Birds, vol. ii. p. 256. 
+ Birds of Berwickshire, vol. i. p. 199. 
§ Ch. Dixon, Lost and Vanishing Birds, p. 198. || Dict. of Birds, p. 87. 
