104 NATURAL HISTORY OF SELBORNE. 
When redstarts shake their tails they move them horizontally, as 
dogs do when they fawn: the tail of a wagtail, when in motion, 
bobs up and down like that of a jaded horse. 
Hedge-sparrows have a remarkable flirt with their wings in 
breeding-time; as soon as frosty mornings come they make a 
very piping plaintive noise. 
Many birds which become silent about Midsummer reassume 
their notes again in September ; as the thrush, blackbird, woodlark, 
willow-wren, &c.; hence August is by much the most mute month, 
the spring, summer, and autumn through. Are birds induced to 
sing again because the temperament of autumn resembles that of 
spring? 
HEADS OF EELS. 
Linnzeus ranges plants geographically; palms inhabit the 
tropics, grasses the temperate zones, and mosses and lichens 
the polar circles ; no doubt animals may be classed in the same 
manner with propriety. 
House-sparrows build under eaves in the spring ; as the weather 
becomes hotter they get out for coolness, and nest in plum-trees 
and apple-trees. These birds have been known sometimes to 
build in rooks’ nests, and sometimes in the forks of boughs 
under rooks’ nests. 
As my neighbour was housing a rick he observed that his dogs 
devoured all the little red mice that they could catch, but rejected 
the common mice ; and that his cats ate the common mice, refusing 
the red. 
Red-breasts sing all through the spring, summer, and autumn. 
The reason that they are called autumn songsters is, because in 
