BRITISH BIRDS OF FASTEST FLIGHT 63 
The flight of the eagle here described was 
obviously a glide or downward flight, when, as I 
have pointed out, gravity would assist his speed to 
a greater extent than it would in a bird of less 
weight — the peregrine. 
In the case of a bird of prey descending from 
a height on its quarry, the nearer its downward 
flight is to the vertical the faster will it descend. 
In coming down on its prey, neither the eagle nor 
the falcon completely closes its wings, probably 
because if it did so, it would lose control. This 
is also true of the gannet or solan goose, which has 
been described as the largest and noblest-looking 
of our sea fowl. The great speed which a bird of 
large size can attain in downward flight can to 
some extent be realised by watching the gannet 
when he drops head first as he descends per- 
pendicularly on to the fish in the water. I have 
carefully examined and compared the skeletons 
of the eagle and peregrine and have tried to form 
some idea as to the relative muscular power and 
driving force of the two birds, and bearing in 
mind the facts stated above, and the greatly 
superior size and weight of the eagle, it seems 
reasonable to conclude on principle that the eagle 
is probably faster than the gyr-falcon or peregrine 
