194 Birds of Colorado 
victim, and often plunging under the surface. The 
structure of its feet, the reversible inner toe, the granular, 
rough soles, the claws of equal length, all strongly curved, 
are all adapted to the capture of fishes. It is frequently 
robbed by the larger and stronger Bald Eagle of its 
hardly-earned prey. 
The nest is generally placed in a tree and is used year 
after year, so that it becomes a very bulky structure. It 
is built up of sticks with various kinds of rubbish added to 
it. The eggs, usually three in number, are very hand- 
some, varying very much in shape and markings. The 
ground-colour is creamy-white and this is marked with 
various shades of brown, sometimes so heevily as to 
conceal the ground-colour. They average 2°45 x 2°0. 
Morrison found fresh eggs at the end of April, while 
Scott thought eggs were laid about June 13th, as the 
female was constantly on the nest after this. These 
are the only two dates I have found for Colorado. 
ORDER STRIGES. 
This order, containing the nocturnal birds of prey 
or Owls, is easily distinguished by the following external 
characters. 
Head very broad from side to side, and the feathers 
arranged to form a ruff or facial disk, radiating outwards 
from the eyes on either side ; bill with a basal, soft-skinned 
cere, at the edge of which open the nostrils ; the base of 
the bill concealed to a great extent by the feathers of 
the facial disk ; edge of the bill never lobed or hooked ; 
eyes forwardly directed, and very large; ear-opening 
often very large. and provided with an operculum or 
movable flap, those of either side often quite asymmet- 
rica and sometimes causing asymmetry in the skull 
