COMMON TO BOTH SEXES 271 



an inch or two below the surface. In fact, one sometimes finds a "breather-hole" through 

 the roof, and birds have been observed with only their heads projecting like a periscope. The 

 occupant of such a roost continues to face the same direction as it did on entering. For 

 this reason, the pile of droppings normally present is on the side toward the entrance. When 

 the snow is loose, it usually fills in behind the bird but it is sometimes possible to see di- 

 rectly into the cavity. Exit is from the opposite side. If disturbed, the bird bursts immedi- 

 ately into flight, scattering snow in all directions; otherwise, it may emerge through an in- 

 clined tunnel and walk away. One often comes upon such deserted shelters looking like rail- 

 road underpasses. 



When diving into the snow, it is probable that the bird holds its head in such a manner 

 that its breast strikes first. 



It has been stated many times that grouse occasionally die as a result of being imprisoned in 

 a snow roost by a crust forming over them, or that they kill themselves in attempting to dive 

 into snow heavily crusted over. While both these conditions may occur, no direct evidence 

 has been secured in the present work. 



Snow-roosting grouse, however, are sometimes quite vulnerable to |)redation. This w-as dem- 

 onstrated clearly during the winter of iy35-36 on the Connecticut Hill study area. Conditions 

 conducive to this habit were much more prevalent than usual and the birds reacted accord- 

 ingly. Field observation soon revealed that grouse, roosting in this manner, were frequently 

 being caught in their burrows, particularly by foxes. That winged jjrcdators may also lake 

 advantage of this characteristic has been shown in several instances where horned owls have 

 been successful in capturing such individuals. 



In this connection, the following experience is interesting. On a day of moderate tempera- 

 ture but with a strong wind blowing, it was observed that a large proportion of the grouse 

 were in snow roosts. As the snow was only six inches deep, it had been necessary for the 

 birds to alight first before forming their burrows and thus those roosts could be located before 

 the birds flushed. By using extreme caution in stalking, a field man was able to capture in his 

 hands two birds out of three attempts. It was found, however, that if one so much as allowed 

 his shadow to fall across the bird's location, it would flush. 



Dust Bathing 



Grouse indulge in the practice of wallowing in "baths" of dust, fine dirt, rotten wood and 

 similar materials in the same way as the ordinary barnyard fowl. The summer season is the 

 time when this habit is most in evidence. It was noted on the Connecticut Hill area, however, 

 during the mild winter of 1932-33, that grouse occasionally dusted during January, utilizing 

 rotten wood in well-sheltered spots where the sun had dried it out. The purpose of this habit 

 is generally accepted to be that of helping the birds to rid themselves of lice and other external 

 parasites. It also aids in keeping feathers in good condition, functioning in much the same 

 way as brushing and combing one's hair. 



These baths may be located either in the woods, in slashings, in small openings or along the 

 edge of larger openings such as clearings, fields, roads or streams — in fact, any spot offering 

 suitable material and receiving the sun's rays during some portion of the day. The bath may 

 be recognized as a rounded depression of about the size of the bird's body. It often contains 

 several contour feathers and sometimes may show evidence of scratching. Another character- 

 istic, particularly of earth baths, is a fine coating of dust covering the adjacent vegetation. 



