Some observations on the predator-prey complex in the Gallatin valley

Some observations of predator-prey re la t io n s were made on a sec tion of land in th e m idst of f i r s t grade i r r ig a te d farming land ly ing ju s t west o f th e Montana S ta te College campus. The study was ca rr ied out between Ootober I , 1939 and A pril I , IgttI e Scat and p e lle t analyses and f i e ld observations were made to t r y to e s ta b lish some of the re la tio n s between the rap t ores and p redato rs aTM* the prey species on the a re a . Despite ample opportunity to prey on domestic animals a l l preda­ t io n was on w ild populations, mainly on meadow mice. In sects were taken in s ig n if ic a n t q u a n titie s when they were a v a ila b le . A ll the predators a te a considerable amount o f ca rrio n in the w in te r. Predators on th is area had no detrim ental e f fe c t on normal prey popu lations. -5 INTEODUCTION The study of predation i s a r e la tiv e ly new aspect of animal ecology. Few workers have investigated, th is f ie ld in d e ta i l , hence any concrete evidence offered in in te rp re ta tio n of p redator-prey re la tio n s i s valuable in helping to complete the p ic tu re . A survey of l i t e r a tu r e reveals the need of accurate data on lo ca l p redation p a tte rn s and the attendant c o llec tio n of h ab it v a ria tio n in d iffe re n t a reas. This p ro jec t was undertaken in order to gather data which would f i l l in p a r t of another gap in th is f ie ld . a S E m c p m r of ideas Early in the Middle Ages w ritten records were made o f the d e stru c tiv e ­ ness of "vermin" to small game and domestic animals. These p redato rs were hunted unceasingly and no sportsm an's code was invoked against the manner of th e i r capture. The ancient thought th a t p redato rs a re "vermin" to be exterm inated bore the im plica tion th a t any carnivore (predator) taking an animal which man wanted fo r h im self was a th ie f and should be punished accordingly. The idea p e rs is ts in the minds o f many even today. However, people in general, and n a tu ra lis ts in p a r t ic u la r , a re beginning to re a liz e the inca lcu lcab le value of predatory species. The re la tio n sh ip s of p redato r and prey species, the in te r re la t io n s of p redato rs— the contemporary concept of p redation—i s yet immature; the e a r l ie s t in ten siv e study of these in te r re la t io n s was begun l i t t l e more than a decade ago. Several pioneers in the study of p redation were McAtee, Stoddard, Leopold, and Errington. These, and o thers, have se t fo r th concisely various phases of the p redation theory which e a r l ie r were not understood or were unknown* Many people do not rea lize Wiat far reaching e ffec ts may resu lt from some seemingly minor disturbance in the b iota of an area* Breticenridge (1958) suggests that most hunters advocating predator control "do not seem to appreciate what tremendously complex and powerful natural forces they are opposing in trying to bring about an unnatural, Utopian situation where game i s continuously abundant* • • They do not stop to figure out that i f they k i l l o f f a l l the hawks and owls that prey to some extent on game sp ec ies , they are a t the same time removing e ffe c tiv e and natural checks on ground sq u irrels, mice, rabbits and lik e forms thsfc in turn destroy cover (and food) for game birds. " Leopold (1933) quotes McLean as saying, "There i s a growing tendency on the part of sc ie n tis ts to defend the predator as indispensable to the welfare of the animal preyed upon. " Cahalane (1939)# reporting on research done in Yellowstone National Park, Modoc Lava Beds, and Mt* McKinley National Monuments, says, "Results of studies brought to conclusion indicate that control (of coyotes) a t present i s not desirable. Rather, on the contraxy, coyotes under present circumstances are exercising a b en efic ia l influence by removing diseased and crippled waterfowl and surplus prey mammals*" These crippled and surplus animals would have to disappear anyway, by migration, starvation , d isease , or death* The ecological concept o f predation in so in f in ite ly variable that laws governing predator-prey relations are d if f ic u lt to formulate* Even though d efin ite rules for interpretation may not y e t be made, certain generalizations convenient for interpretation o f data are in order* 6 -