BIRD RECORDS OF THE PAST WINTER, 1917-1918, IN 

 THE UPPER MISSOURI VALLEY. 



T. C. STEPHENS. 



This report, like the one for the preceding winter,^ is a com- 

 posite one. It includes the observations of a number of other 

 field students besides . myself , And I wish to acknowledge such 

 assistance from Mr. A. J. Anderson, Mr. A. F. Allen, Mr. G. 0. 

 Ludcke, and Mrs. H. M. Bailey, all of whom have done more or 

 less field work during the past winter season. 



It has seemed proper to indicate in the title of the paper 

 the wider range from which many of the specimens recorded 

 have been received. Some of the specimens referred to have 

 been received from Nebraska, IMtinnesota, North and South 

 Dakota, and Iowa. Aside from the notes on this material, the 

 paper is based upon local field work. 



In nomenclature the writer has followed the A. 0. U. Check 

 List, except in the matter of subspecific designation. In a great 

 many cases the subspecies can be determined only by experts 

 at institutions where large series of skins are available for com- 

 parisons. As these notes are not intended as a contribution 

 on the distribution of subspecies, it seems best to omit the tri- 

 nomial designation, even where the subspecific rank might be 

 fairly inferred on the basis of geographical location. Tri- 

 nomials are used in two or three eases where the American 

 form is regarded as a subspecies of an extralimital species. 



This winter has been marked especiallj^ by the very unusual 

 flight of several species of raptorial birds, especially of Snowy 

 Om4s and of Western Horned Owls. The American Game Pro- 

 tective Association has recently gathered information- whicli 

 seems to relate these invasions of northern birds of prey to the 

 periodical scarcity of rabbits in those regions. The facts thus 

 presented indicate that there must have been a marked decrease 

 in the numbers of rabbits and varying hares in the Canadian 

 provinces and northern United States in the falls of 1916 and 

 1917. In the paper referred to it is suggested that the decrease 

 in these mammals is due to a disease. At anv rate it was during 



^Bird Records During the Past Winter, 1916-1917, in Northwestern Iowa. 

 By T. C. Stephens, Proc. Iowa Acad. Sci., XXIV, pp. 245-258, 1917. 



^'hy Grouse are Scarce. By John B. Burnham. Bulletin American 

 Game Protective Ass'n., January, 1918. 



