THE OSPREY. 25 
I am informed by Mr. W. W. Worthington, of Shelter 
Island, New York, that the period of incubation is twenty- 
four to twenty-eight days. When the young hatch, the old 
bird seldom if ever removes the egg-shells from the nest. 
They are frequently to be found lying on the edge of a 
nest containing well-grown youngsters, and at other times 
the crushed fragments are mixed with the nesting-material 
under the young birds. 
When he makes his first appearance in the world, the 
baby Osprey is covered with a short, firm down, more 
like fur than feathers (Plate 62). It is striped longitudinally 
with brown and buff. Like smaller birds, he is provided 
with a supplmentary knob on the upper mandible, to assist 
him in breaking his way through the ege-shell. His eyes 
are open from the first. The naval cord is unusually 
conspicuous in the centre of a circular area of bare skin. 
At first the cere and feet are pink, and the toes are arranged 
as in the majority of birds, namely three to the front and 
one to the rear. Not until later is the evolutionary adapta- 
tion of the reversability of the outer toe developed. The 
interior of the mouth and tongue of the new-born bird 
are red. When approached, he holds up his open mouth 
for food, in the instinctive manner of smaller altricial birds. 
His only utterance is a single, weak monosyllabic sound. 
He is very susceptible to the direct rays of the sun, and 
exhibits great uneasiness even on a moderately hot day. 
In view of the usually unsheltered situation of most Ospreys’ 
nests, it is plain to see how essential to the welfare of the 
young is the parents’ protecting shade. ‘The mother 
bird is well aware of this fact, and when her babies are 
callow, will often exhibit heroic courage in her eagerness 
to afford them the shelter of her body. 
As the down grows it becomes fluffer, and the light and 
dark tracts are more contrasted in colour. Meantime the 
feathers, in their dark, pulpy sheaths, have been pushing 
their way through, and soon the down from their tips 
may be found clinging to the sticks in the net. In the 
