LIFE IN A PINE WOOD 11 
of the vigilance and extraordinary secretiveness of 
the parent birds. Never once had they uttered a 
sound or allowed themselves to be seen. Now 
that their young were out and able to fly, they no 
longer found it necessary to make themselves in- 
visible on the appearance of the human form in 
the wood. At all events, after keeping the young 
concealed for the space of three or four days, they 
began to show themselves openly, pursued by the 
young, wailing and screaming to be fed. All day 
long these whining cries were heard, and it was 
plain that a new system had been adopted by the 
parent birds at this stage, which was to keep their 
young on short commons, instead of supplying 
them with more food than they could consume. 
The result was that the young, instead of sitting 
idly waiting for small birds, properly plucked, 
to be brought and dropped at their feet, were 
driven by hunger to fly after the parent birds, 
who led them an endless chase in and out and 
above the trees. It all looked like a great waste 
of energy, but it had an important use in teach- 
ing the young to fly and to develop the wing 
muscles by incessant exercise. These exercises con- 
tinued for five or six days in the wood, then followed 
a fresh move; every morning early the wood was 
quitted by the whole family, the young, no doubt, 
being conducted to a clump on one of the extensive 
tracts of heath in the neighbourhood. There they 
would have other and more important lessons to 
learn. The young hawk would have to pluck the 
