The Bird ItseK 11 



the barbs and barbules are few and stiff in the auriculars to allow 

 free passage of sound; and in the anal feathers and those of the oil 

 gland the aftershaft is practically gone. 



The aftershaft is well developed in the ruffed grouse in all teleop- 

 tiles except the rectrices and functional remiges; in the anal and oil 

 gland feathers, as noted above, it is often not distinguishable; it is 

 rather poorly developed on the alula quills, axillaries, and the 

 auriculars. It is always plumulaceous (i.e., downy or fuzzy) and pig- 

 mented only at the tips of the longest barbs. 



Sexual Variations in Feathers. Variations in the pterylosis between 

 the sexes are minor. The number of feathers modified to compose the 

 ruff is greater in the male. There is a tendency for the male to have 

 more feathers than the female, possibly due to his larger size. The 

 size of some of the feathers, as the rectrices, is larger in the male. 



Snowshoes. These are cuticular outgrowths along the edges of the 

 toes that grow in the fall and shed in the spring. Their purpose is to 

 assist the biid in walking on snow by widening the toe area— hence 

 the name snowshoes. Normal length is about two millimeters but in 

 the northern subspecies tend to grow a little longer. 



Moult. The ruffed grouse has a single moult each year. With the 

 immature birds this takes place in August and September when the 

 juvenile plumage is replaced by the first adult feathers. There is 

 some evidence that the outer primary in this first adult plumage is 

 shorter than in subsequent years. 



The adults begin their annual moult in late July and continue into 

 September. There is a period when many of the flight feathers have 

 been dropped and the new ones are not well developed that the 

 birds have some diflBculty with flight. At this time it is not uncom- 

 mon to see a "tailless" grouse. 



It has been believed by some that a restricted pre-nuptial moult 

 takes place in the ruffed grouse. This was originally based on two 

 specimens of B. u. sahini described by Dwight (1900), which were 

 collected in British Columbia in 1889, one on May 20 and the other 

 on June 2. These specimens have been re-examined by Trainer who 

 likewise found a few growing feathers on the head and throat 

 regions (letter, January, 1942). He says, however, that the evidence 

 indicates that these two birds are unusual and that the normal thing 



