Tails A413 
the borders of streams. We are all familiar with the tip- 
ping of the tail in sandpipers, and, including the Green 
Heron, we will see much the same motion in birds which 
haunt the stream borders; even in the Water Thrush the 
same habit prevailing, although, as we saw in the pre- 
ceding chapter, this bird is closely related to the bright- 
coloured warblers of our tree-tops. The wagtails have 
received their name from this same habit, of which no 
explanation has yet been offered. 
The Road-runner, a ground cuckoo of the Western 
plains, has a tail as long as its entire body, which is as 
expressive as the gestures of a Frenchman. When sitting 
quietly in the shade of a mesquite-bush in Mexico, I have 
seen one of these birds dash into sight and drop, like an 
arrow, upon a luckless lizard. At the moment of attack 
all ten tail-feathers of the bird were wide-spread and 
a-tremor, indicative of the extreme excitement attendant 
upon the capture of the reptile. While eating what choice 
parts were desired, the tail was folded and lifted out of 
the way. Soon the bird spied some motion of mine, and 
with the suspicion came the high extended neck, while the 
tail turned up and forward, until almost touching the 
bird’s head. A second motion on my part, and the tail 
manceuvred to a line and trailed limply after the bird, 
as it half-flew, half-leaped to a high rock and on out of 
sight. 
The white under sides of the tails of the wild rabbit 
and the white-tailed deer have been explained as warning 
signals to others of the family or herd: white guides 
which the less experienced members may follow and so 
