348 Birds. 
but are not now so frequently seen in England as for- 
merly. In their flight, Cranes mount high in the air, 
but their voices can be heard even when the birds cease 
to be perceptible to the eye, and it is said that their 
sight is so keen that they discover at a great distance 
any field of corn or other food which they are fond of, 
and presently alight and enjoy it. These depredations 
they generally commit during the night, trampling down 
the ground as if it had been marched over by an army. 
They generally form themselves in the air in the shape 
of a wedge. 
" Part more wise, 
In common, ranged in figure, wedge their way, 
Intelligent of seasons, and set forth 
Their aery caravan high over seas 
Flying, and over lands, with mutual wing 
Easing their flight. So steers the prudent Crane 
Her annual voyage, borne on winds. The air 
Floats as they pass, fann'd by unnuinber'd wings." 
Milton. 
This bird lives to a considerable age, and as it is 
easily tamed, it has been ascertained that the Crane 
often reaches his fortieth year. Its nest is usually built 
amongst the reeds and sedges of a marsh, but sometimes 
upon a ruined building. The female lays two eggs, of a 
pale brown colour, with darker spots. 
According to Kolben, they are often observed in large 
flocks on the marshes about the Cape of Good Hope. 
He says he never saw a flock of them on the ground 
that had not some placed apparently as sentinels, to 
keep a look out while the others are feeding, who on the 
approach of danger immediately give notice to the rest. 
These sentinels stand on one leg, and at intervals stretch 
out their necks, as if to observe that all is safe. On 
notice being given of danger, the whole flock are in an 
instant on the wing. Kolben also adds that in the night 
time each of the watching Cranes, which rest on their left 
legs, hold in their right claw a stone of considerable 
weight, in order that, if overcome by sleep, the falling 
of the stone may awaken them. 
