34 OUR BIRD ALLIES. 
in one of his published letters, employed his powers 
of sarcasm upon this theory with crushing effect, 
although he did not think it necessary to put forward 
any more plausible explanation :— 
‘Supposing your theory to be true,” he writes, 
“then indeed has Dame Nature most cruelly punished 
your ‘ type,’ the barn-owl; for even in the month of 
June she directs this bird to hunt for mice, and she 
shows it how to catch them when the sun is blazing 
in a cloudless sky. This I myself have seen re- 
peatedly. ‘To what intense pain must this poor bird 
be doomed, if its feathery ‘ facial disc’ has the power 
of reflecting the burning rays of the sun upon its 
eye! If the facial disc could reflect this, the barn- 
owl would assuredly be aware of it, and she would 
either, in common prudence, keep her room till night- 
fall, or borrow a parasol to protect her eyesight from 
the flaming luminary. 
‘““Tf the dame judged it necessary to furnish your 
‘type’ with this ‘ facial disc,’ in order to increase its 
power of nocturnal vision, we must lament that the 
bittern, the heron, the wild duck, and many others 
have been sadly neglected by her; for none of these 
birds have that which you term ‘ facial disc,’ still they 
all search for food in the darkest night, and wing 
their way in safety through the darkest sky.” 
Strangely enough, Waterton omits to mention two 
far more conclusive arguments, which of themselves 
are amply sufficient to refute the theory in question. 
The first of these 1s that in many owls the feathers 
of the disc are brown, and so would absorb the light 
