154 



THE POPULAR SCIENCE MONTHLY. 



geoiis when the safety of person, or home, or young, is in danger. 

 There is not much of the owlish face in our Surnia. The facial disk, 

 so prominent an owlish trait, is by no means marked. Still, for all his 

 looks and ways, this same Surnia is a true owl. To an unusual degree 

 for his family, he is trim, compact, and graceful. Its favorite home is 



Fio. 10. The Hawk-Owl (Surnia ulnla). 



in the arctic regions, where "it feeds chiefly on the field-mice {Aru-i- 

 culce) which swarm in the sphagnous vegetation of those boreal 

 lands ; also upon small birds, grasshoppers, and other insects." In 

 severe winters it comes southward, even to the Middle States. 



The old philosophers said Nature abhorred a vacuum. Does it 

 not appear from our owlish restane that Nature has an aversion to the 

 abrupt and disconnected ? Is it not noticeable that, however natural 

 any two great related groups of animal forms may be, they are not 

 separated by sharp and wholly distinctive lines ? There is a shading 

 at the edges into each other. In Biblical speech, the progress of 

 the Divine scheme is literally " little by little," and the lower group 

 gives of the higher one, as Bishop Horseley in a different connection 

 has said, " elegant adumbrations of sacred truth." Only when the 

 extremes of the groups are set in contrast will the family differences 

 best appear. Let one but look a barn-owl and a bald-eagle full in 

 the face of each, and how clear their differentiation ! But these are 

 the typical representatives here brought face to face. Suppose we look 

 a moment at Fig. 11, of the marsh-hawk, or harrier [Circus cyaneus^ 

 Linn.), and then recur to Fig. 10, of the day-owl, or Surnia. Now 

 the differentiation almost fades away. How very like they are ! But 

 Surnia belongs to a more lowly tribe than does Circtis. The marsh- 

 hawk is an unmistakable falcon, and the other is assuredly an owl. 

 But as respects this harrier, however clear as a whole the title to his 



