20 Mr. J. Blackwall’s Ornithological Notes. 
nessing the fascinating effects ascribed to the music of this ima- 
ginary siren. 
The red-backed shrike may frequently be seen to take insects 
when on wing, like the Muscicapide. 
The Whinchat, Sazicola rubetra. 
In Denbighshire this pretty migratory bird arrives about the 
end of April, when the song of the male, which is sometimes 
delivered on the wing, may be heard repeated at short intervals. 
After the female has hatched her eggs, both sexes commence 
the call from which the species receives in Lancashire, where it 
is abundant, the provincial name of vtick ; the accent falls on the 
note supposed to resemble the first syllable of the word, and the 
second note of the call is sometimes repeated ; thus,—ttick tick. 
I have seen the whinchat pursue the red-backed shrike with 
cries and gesticulations expressive of extreme animosity. 
The Sedge Warbler, Sylvia phragmitis. 
The late cold spring of 1847 exercised a very marked influence 
upon the vocal powers of our migratory warblers ; the notes of 
the sedge warbler, which were not heard in the neighbourhood 
of Llanrwst till the 14th of May, were so defective in tone that 
this species found it quite impracticable to execute its song, 
being enabled by the most strenuous efforts to perform a few 
passages only, and those in a very imperfect manner ; even the 
high powerful strain of the black-cap, Sylvia atricapilla, and the 
deep rich melody of the garden-warbler, Sylvia hortensis, were 
reduced to a few short, abrupt, feeble sounds without any ap- 
parent connexion or modulation ; our resident singing birds also 
were sensibly affected by the severity of the season, all attempts 
to deliver their lays with their accustomed vigour and facility 
beimg totally unavailing. As the temperature increased with the 
advancing year, a corresponding improvement was perceptible in 
the wild music of the fields and woods, until the full flow of song 
announced the pleasing intelligence that the summer was at last 
confirmed. Now as it is evident, from the facts already stated, 
that a relation must exist between the singing of birds and the 
temperature of the atmosphere, I shall briefly advert to some of 
the circumstances which appear to constitute that relation. 
An idea seems to have been entertained by the Honourable 
Daines Barrington that the periodical cessation of the songs of 
birds may possibly be caused by. some physical impediment, as 
indicated by the following paragraph extracted from the fifth 
letter addressed to that gentleman by Mr. White in his ‘Natural 
History of Selborne 2—* Your supposition that there may be 
