WILLOW PTARMIGAN l8l 



very numerous again and total disappearance in 1876; 

 1882, a few observed; 1883, 1884 and 1885, great 

 abundance; 1887, disappeared entirely; 1891, a few 

 seen, gradually increasing each year till 1895, when 

 there were considerable quantities; 1897, none; 1903 

 and 1904, abundant, and a few seen every winter since 

 to date, 1909. 



"At one time it was supposed that these years of 

 abundance on the coast were due to heavy sleet in the 

 interior, covering up all the buds and preventing the 

 birds from feeding, and thus forcing them to seek food 

 elsewhere. I have noticed that this will affect them 

 to some slight extent, but the dates given show too 

 much regularity for this to be the true cause. My be- 

 lief is that it is due to the food supply. Having ex- 

 amined thousands of the crops of these birds I found 

 that over ninety per cent, contained the buds of a 

 species of willow, popularly known here as pussy wil- 

 low, Saiix arcticaf The balance were buds of the 

 birch, poplar and the mountain ash and its berry. I 

 also noticed a few seeds that I could not identify. 



"After a year or two of great abundance, all the 

 willows are destroyed by the breaking of the tips and 

 the buds, and the shrub takes about two years to re- 

 cover, which is generally by fresh sprouts from the 

 roots. As the food fails the birds have to move else- 

 where. It would, therefore, appear from my data 

 that it takes about ten years to go around their circle 

 of migration. I say circle because their line of flight 

 seems to indicate this. They first appear on the 



