.•^+6 



P RE DAT 10 \ 



Effect on Predators 



In general control was effective primarily during the season iinnieHiately involved. Of the 

 more important grouse predators oiilv the weasel seemed to recuperate slowlv as indicated 

 by a comparison of the numbers taken during the successive years 1930-31 and 1931-32*. 

 The lower take of great horned owls the second season means little since most of the win- 

 ter population of these birds were visitants from farther north. Likewise the majority of the 

 specimens of migratory hawks were undoubtedly transients and thus would have slight 

 effect on the abundance of such species from year to year. \^'ith respect to the Cooper's 

 hawk and sharp-shinned hawk their numbers were least affected, even while control was 

 being carried on. 



Another aspect of this question involves the fact that the coverts on Connecticut Hill which 

 were used for these tests were in no way separated from similar surrounding territory. This 

 condition undoubtedly resulted in a certain amount of influx of predators into the test plots 

 as the operations proceeded. Nevertheless most game managers interested in the possibilities 

 of this practice would be confronted by the same situation. 



Valcour Island, on the ollici liand. is more isolated. But hawks and owls trade back and 

 forth from the mainland and even foxes and other mammals can cross to it during the win- 

 ter on the ice. 



Results During Each Life Period 



In discussing the results of these experiments it seems most logical to consider the data 

 according to the three life periods of the bird as has been done under previous topics. 



Nest Period 



The experiments on Coiuiecticut Hill |pro\c(i effective in reducing nest losses as shown 

 by comparing the degree of mortality observed on the test area with that on the check area 

 (table 46). 



TABLK 16. r.OMI'MilSON OF NKST MOin'M.ITV ON VHKV SUn,IK( .TI-.O TO PMKD \TOH 

 CONTROL AND ON CHECK AUEA COiNNECTlCLT 111LI> 19;U-l'«.-> 



*Cnntrol limitflH to foxes niiH wennels. 



It is at once apparent ibal. while llic general l<\cl (if iiiiirlalil\ varied ((insiderablv during 

 these years, the cotilrollcd ;iica snlTcicd a inaikiilU Inuir loss each year llian llir clicik area. 

 As discussed elsewhere practicalK all such losses ha\e been attributable hi predators. The 

 difference, thcicfore, may be considered a dire<t result of the predator reduction accom- 

 plished, lurthi'i proof of this effectiveness is llie fail that in \'>'M the areas used were 

 reversed as to treatment from the arrangement <>f 19.SI and 19.'^2. 



* A summary liy ■)>rrjri is incluJvU in itir Appcntlix. |i. 875. 



