manifest from the fact that the eagle can bear off a victim 

 equalling himself in weight. Should he miscalculate, he can 

 always drop his burden, or lessen its weight by eating part of 

 it on the spot. Not so the osprey, or the sea-eagle, which 

 have been known to plunge down and drive their talons 

 into fishes too large to be raised. Unable to release their 

 grip, death, by drowning, has inevitably followed. 



Sometimes the burden is a passenger, instead of a victim. 

 One of the most striking of the coloured Plates in this volume 

 is that of a woodcock carrpng one of its nestlings to a distant 

 feeding-place. This habit is well known. It is not often 

 that the necessity arises, but there are occasions where 

 suitable nesting and feeding grounds cannot be found together, 

 or when, as during prolonged drought, the normal feeding 

 area dries up. Then, instinctively, the parent will surmount 

 the dangers of starvation for their offspring, by conve3ang 

 them to a land of plenty, returning again to the shelter of 

 the wood as soon as the meal is over. The weight of a 

 newly-hatched nestling, it is true, could scarcely be called a 

 " burden." But they are carried about thus until they are 

 strong enough to perform the journey for themselves. Thus, 

 then, towards the end of the nursing period the weight to be 

 carried is by no means a light one. 



But it was shown, long since, by direct experiment, that 

 the area of a bird's wing is considerably, in excess of what is 



46 



