tention. Two of these pairs 
were so uniformly persistent 
in their movements that I 
noted the same carefully. 
"In one case the attacking" 
iish would drive its unresist- 
ing companion half out of the 
water on the lower bar by 
biting" vigorously at the tail, 
and then leaving it stranded 
in the scorching sun would 
return to the upper end of the 
pool until the other fish, after 
slowly wriggling its body 
around, would re-enter the 
pool, when the attack would 
be renewed in precisely the 
same manner. This continued 
during two hours' observa- 
Pliolo by George Sliiras, 3rd 
Fi;maLE of WII.LOW PTARMIGAN STANDING e;rECT, 
AND WITH the; young STANDING IN 
INSTINCTIVE IMITATION 
Photo by George iliua.^. 3rd 
FEMALE OF SPRUCE PARTRIDGE 
467 
