172 THE STORY OF THE BIRDS. 
the tip of the wing is usually formed by the outer 
feather, or else the next one or two are very little 
longer than the outer; and the wing is not so broad 
or concave, nor is it fluttered so rapidly as in the short 
flyers. 
Usually such birds do not suffer themselves to be 
approached, or they are tree haunters or haunt other 
safe places. Sometimes birds combine ground habits 
with very long flight, especially in migration, and a 
few long-winged birds, as the snipes, may skulk and 
hide and allow themselves to be approached ; but 
when they fly up they do not rise so quickly upward. 
They usually go swiftly away near the ground. 
In fact, only a very few light birds among those 
that are long-winged can fly quickly directly upward. 
They must skim away in order to get wp. Some of 
these, as the albatrosses, boobies, etc., can not rise 
from a flat surface, but must paddle along awhile 
with their feet till they get agoing. This is also the 
case with some rather short yet pointed winged water 
birds, as Joons, some ducks, ete., which can be watch- 
ful and have no need to rise directly upward. 
But many of the grouse forms can hur] themselves 
directly from the earth into the air with tremendous 
velocity, especially when their muscles are fresh ; for 
they are not only endowed with a special wing, but 
with rather unusually large chest muscles, which are 
capable of great exertion for a short while only. 
A great compensation for deficiencies in various 
wings is found in both the quantity (bulk) and quality 
of these chest muscles. In some plovers, with such 
