openings (i.e. clearcuts) may in some cases be "beneficial" to boreals because 

 they create edge habitat which the owls use for hunting. It should be noted 

 however, that man-made openings are often accompanied by the potential for 

 human disturbance such as road traffic or firewood cutting, which may not 

 benefit the owls. The potential also exists for the invasion/colonization of 

 these openings by competing owl species such as Great horned, saw-whet, or 

 barred owls (Strix varia) . Such invasions may have a negative effect on boreal 

 owl management goals. Additional research is needed to clarify the 

 relationship between owl habitat use and forest management. 



Regional variation of both calling activity of male boreals and breeding 

 success of nesting pairs has been noted (Hayward et al. 1986) . These 

 variations are apparently a direct result of fluctuations of prey populations 

 and/or availability. These findings are particularily significant in their 

 application to the design and duration of owl surveys and monitoring. 



Short term (one- two years) preliminary surveys cannot take into account 

 yearly fluctuations in calling activity, which could influence management 

 activities in the area with potentially drastic results. Additionally, as this 

 study shows, an apparent regional difference in owl densities exists between 

 the east and west sides of the Continental Divide. If management were directed 

 solely by this one year study, without taking into account the possibility of 

 regional variation in calling rates, very little management for boreal owls 

 would take place on the eastern Districts due to few or no owls found there. 

 Additional survey years may result in very different results, and should serve 

 to assemble the necessary data describing boreal owl distribution and abundance 



over the study area. 



i 

 As a suggestion for further research, boreal owl surveys should be 



continued in southwestern Montana with initial emphasis on nest location 



13 



