14 Taverner, Birds of Red Deer River, Alia. [j^ k 



who were familiar with them and their tales tallied closely. First there 

 were great numbers of the birds and then they disappeared suddenly and 

 without apparent cause. Coincidently numbers of " large gray hawks " 

 and " big owls " appeared in the late fall and winter. Had the disappear- 

 ance been principally due to overshooting, some birds would have been 

 overlooked in the more out of the way localities; but, while the common 

 report was that there had been little if any shooting on many parts of the 

 river valley, the scarcity was general and we did not see a bird except as 

 above. Correlated with the appearance of the raptores and the disappear- 

 ance of the grouse of all kinds was the disappearance of the rabbits. It 

 was the same story wherever we were in 1917: Shoal Lake, Manitoba; 

 here on the Red Deer River; in British Columbia at Hazelton, and in Jasper 

 Park, Alberta. In the last named place at least, overshooting cannot 

 be blamed for the scarcity of grouse, as there is no shooting allowed there, 

 and such small amount of poaching as might have taken place could not 

 possibly have accounted for the almost total absence of birds. Also the 

 widely scattered localities, practically all of central and western Canada, 

 though perhaps less so in the mountains where heavy timber gives good 

 cover, is suggestive of other causes than local shooting. I think it is 

 evident that the occurrence of the well known rabbit disease that periodi- 

 cally decimates these rodents deprived the large raptores of their usual 

 food and forced them to invade southern sections in unusual numbers and 

 turn their attention to grouse. The Ruffed Grouse, living in the heavier 

 timber where cover is better, suffered less than the more open country 

 species. Without doubt when their usual food supply, the rabbit, is cut 

 off, the large raptores constitute a serious destructive influence. It is an 

 interesting study in the correlation of species and complicates the subject 

 of game protection. All that seems possible to do under the circumstances 

 is to encourage the killing of the large winter raptores, yet if this is carried 

 too far the rabbit pests are likely to increase in normal years to a dangerous 

 extent and in the present state of misinformation the ordinary farmer and 

 shooter are likely to involve in destruction the useful species of Buteo 

 and Archibuteo, birds that the prairie provinces cannot well spare. I 

 will discuss them and their effects under the subject of Red-tail Hawk. 

 Horsbrough refers his specimens to campestris, which is the geographical 

 probability. The condition of plumage makes me unwilling to pronounce 

 upon the subspecies. 



57.* Zenaidura macroura. Mourning Dove. — Not very common. 

 We heard of a pair breeding near Camp 1. One was heard the morning 

 of July 10 at Ross's Ranch and another at Drumheller the 14th. One 

 was noted the 18th above Steveville and one taken the next day between 

 that village and Camp 11. Horsbrough records a single specimen from 

 Buffalo Lake. 



58.* Cathartes aura. Turkey Buzzard. — We saw the first Turkey 

 Buzzards shortly after we entered the real Bad-lands above Camp 5, Ross's 

 Ranch. From then on several or more were noted daily. At Camp 11 



