8 _REPORT ON THE MIGRATION OF BIRDS. 
bound stations. As shown in one case, positive assurance is 
given by the reporter at Noss Head, that for eleven years 
scarcely a bird “had been observed on migration day or night,” 
and we have scarcely any statistics to show a contrary view, as 
regards the said area all through our seven reports. 
Now, it is known with considerable certainty that Caith- 
ness owes its periodical passing visits of such species as 
Blackcap and Pied Flycatcher, both in spring and autumn, 
to its immediate proximity to one of the chief highways of 
migration—the Pentland Firth; and the configuration of the 
N.E. peninsula of that county clearly points to the route by 
which spring passing migrants reach the E. coast of the county, 
as we have already explained in previous remarks. They 
cross over a low-lying depression in the land from Dunnet 
Bay, and cut off the peninsula of Canisbay. Coming again in 
autumn, the same birds, to some slight extent, may return 
across this peninsula, but the undoubted fact remains that the 
compressed and strongest flights cross over the Pentland Skerries 
and through the Firth. 
In the same way, it appears that while scarcely a bird 
is ever recorded at the stations along the E. cliff-edge of 
Aberdeen, yet, in autumn, a well-marked stream of migration 
enters the N.E. counties at a point westward of Troup Head, 
which forms the northern abutment of the dividing ridge, or 
watershed, between what are known as the Faunal areas of 
“Moray and Dee;” and that thence up the wide open valley 
of the Spey, and over the low-lying portions of the south coast 
of the Moray Firth, this stream is clearly traceable at many 
points. It is also known that an equally decided spring 
“return” descends the same great valley, and enters it across 
the dividing range between the head waters of Spey and Spean 
or Pattack. We have studied this subject locally—at many 
points personally—especially in spring, and notes we have taken, 
dating back for many years, all tend to strengthen the statement. 
In the same way it appears almost equally certain, that while 
few birds fly across over the cliff-edges of Berwickshire, but 
pour in vast streams up the open and wide Firth of Forth, still 
Berwickshire, and the interior of the south of Scotland, are well 
supplied with migrants; and the “return” is equally apparent. 
A study of our previous remarks by our readers cannot, we 
