Sick or dead marimals and "birds are difficult to find. The color- 

 ation of aninials, wMcli blends into tlia colors of the environraent, offers 

 little contrast to attract the eye. Furtnermore, the tendency of sick 

 animals to secrete themselves and to reraain quiet also aids in their es- 

 caping obserYation, Dead animals are rapidly disposed of "by scavenger 

 mammals, birds, and insects, and in a short time no trace of the car- 

 casses remains* Thus it nay happen th^at a dense population may he almost 

 v;iped out hy disease, and yet few evidences reujain to attrau:t the atten- 

 tion of the casual observer* 



In connection with the cooperative studios now being conducted, 

 efforts are made to collect for laboratory examination specified ntLmhcrs 

 of grouse and hares at regular intervals from representative areas, and 

 to procure for stud;>' all grouse and hares found sick or dead» Sfveral 

 diseases that are fatal to tnese species mvo been recognized*' It was 

 demonstrated that the cottontail rabbits were wiped out by tularemia 

 over a large areo. under invo-^.tigation. The sno'.<shoe hare and the grouse 

 are irore resistant to this infoctionj but the disease is also found in 

 these as well as in other important species despite their greater natural 

 imm^X'iity, 



The immense numbers of ticks o,nd other biting paro.sites that every- 

 where aboujid and &j.'e capable of trans'mitting infectious diseases furnish 

 ample raeaur for the spread of virulent orgeriisras to almost every wild 

 manmal and bird. It is not unusual to find several thousand ticks on a 

 single specimen* ?or example, on a tj'jsicrl area in Minnesota in August 

 1935i the average infestation of ticks per snowshoe hare wo.s 3»^^^^-l-» the 

 numbers ranging from 3SS to Oj5b^-* With such massive parasitism by two- 

 host ticks, the rapid spread of disease orge^nisms is definitely assured* 

 Purtherm.orcj one must also take into account as possible carriers of dis- 

 ease the great number of biting flies and other insects that toke their 

 living from the blood of v/ild anim.als. 



In addition to t'alaremia, other diseases that are knovm to be 

 sprea.d by contaminated or polluted environment have been discovered 

 prevalent in game* Bird cholera and ulcerative enteritis have been 

 observed in grouse, and paratyphoid h^s been found in ha,res. Several 

 other fatal forms of disease, the cause of which is not yet known, i:iave 

 also been noted* One feature of the research investigations in progress 

 is the examins^tion of all abnormal Conditions noted in the study speci- 

 mens ti'iat ir.ay acco"ant for losses in wildlife* 



The more or less sudden disappearance of certain species of game 

 occurs reg-ularly where there are dense populations* ''<7here anim.als are a^ 

 buiidant the possibilities for the spread of disocase are greatest, as great 

 concentrations increase the opportunity for infections to be carried by 

 parasites or oth.er means from, one host to another* Likewise in dense 

 populations pollution of the range reaches the maximum, and the consequent 

 spreo.d of parasites and disease may be exceedingly rapid, 



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