THE WOOD WARBLER, 369 



of the birds, however, has the slightest resemblance to the 

 wrens in form or in general habits, although they have both 

 got the name. 



The difference in note between the wood warbler and the 

 two birds with which it has been confounded, is as perceptible 

 as the distinction in appearance. The note of the wood 

 warbler is the single syllable twee ; but it not only varies that 

 so as to make almost an octave of it, but runs the last repe- 

 tition of the stave into a peculiar hissing and whistling trill, 

 from which it has got the specific name of sibilatrix (the 

 hisser or siffler) ; and in the delivery of that the bird is agi- 

 tated in a very peculiar manner. The lesser petty-chaps has 

 also only a single note ; but it repeats that twice with dif- 

 ferent intonations, so that it has got the name of chip- 

 chop, or chiff-chaff. Indeed, it is accused of falling into 

 the habit of the people of the district which it frequents, in 

 substituting one for another of those letters that belong to 

 the same organic expression with f; being chiv-chov, chiff- 

 chaff, chib-chab, or chip-chop, according to the locality. 



That is not unlikely, as birds have great flexibility of voice, 

 and great powers of imitation ; and, as there is unquestion- 

 ably an unexplained something in the air and climate of dif- 

 ferent districts which influences the pronunciation of the 

 people, it is natural to suppose, that it should also affect, not 

 the songs of birds only, but the voices of all animals. The 

 voice of a dry chink or a dry leafless tree is harsh and sharp 

 to the wind, compared with the same when they are humid ; 

 and it is open to observation, that the voices of the inhabi- 

 tants of dry places are not so soft as those of moist. Com- 

 pare Westmoreland and Cumberland with Durham and 

 Northumberland ; and compare the whole western side of 

 Scotland with the eastern; nay, compare Essex with the 

 maritime part of Somerset, and they are both champaign coun- 

 ties, though Essex is by much the drief of the two. The 



VOL. I. 2 B 



