322 SUMMER. 



than in the north-west. It does not follow from that, 

 however, that there must upon the whole be a greater 

 variety of summer birds in two parts of the country, 

 whatever may be their difference of elevation, if there 

 be the same abundance of food for them in the one as 

 in the other. The law of nature, as observed in the 

 facts, is, that wherever there is, upon the average of 

 seasons, food for them, to that place they repair ; and 

 when we find, from the facts, that any thing is a law 

 of nature, we may save ourselves the labour of 

 enquiring why it should be so, until we have found 

 out the more general cause why a stone falls to the 

 ground ; because those general laws are the ultimate 

 facts, and of course all speculation beyond them is 

 mere fancy ; and being error, it cannot possibly tend 

 to any information. But we must not forget 



THE WARBLERS. 



Of the warblers (Sylvia, so called because the most 

 musical of them sing in the woods, or, at any rate, 

 upon trees or bushes) there are thirteen or fourteen 

 different species met with in Britain. Two of these, 

 the Dartford warbler, which is a very local bird, pro- 

 bably confined to England south of the Thames, and 

 by no means general even there ; and the redbreast, one 

 of the most common birds, and one that is far more 

 characteristic of the winter than of the summer, are the 

 only ones that are permanently resident. The others 

 arrive in April or May, a little sooner according to the 

 latitude or nature of the season ; they usually become 

 mute about the time of the solstice, and retire in Sep- 

 tember ; though that, like their arrival, depends some- 

 thing upon the season. They are all insectivorous, 



