INTRODUCTION 

 The boreal owl ( Aegolius funereus ) is a highly nocturnal owl 

 which inhabits northern hemisphere coniferous forests around the 

 world. They are generally 21.5 to 30.5 cm long (Farrand 1983) and 

 weigh 100-140 gm (Earhart and Johnson 1970) . Boreal owls are small, 

 brown owls with many white spots on their crown, nape, and back. 

 Yellow eyes and a yellowish bill are framed by distinctive black 

 facial frames which are spotted with many small white spots. Their 

 white underparts are streaked with chocolate brown. Juveniles are 

 dark chocolate brown with white spots across the back and white 

 eyebrows and cheek spots. 



Boreal owls are secondary cavity nesters, usually occupying 

 cavities constructed by the northern flicker ( Colaptes auratus) or 

 pileated woodpecker ( Dryocopus pileatus ) . Boreal owls will also use 

 artificial nesting boxes (D. Center per. comm.). Boreal owls are 

 territorial and a nesting pair will actively defend the area around 

 the nest site (D. Genter per. comm.). After the courtship in March 

 and April, 4 to 6 pure white eggs are laid. The eggs are incubated 

 for 27-28 days by the female and the young fledge 28-33 days after 

 hatching (Terres 1980) . Boreal owls prey mainly on small mammals, 

 primarily redback voles ( Clethrionomys gapperi ) but also pocket 

 gophers ( Thamomys talpoides ) . shrews (Sorex spp.), and deer mice 



( Peromvscus maniculatus ) . Some insects and birds are also eaten 



(Hayward et al. 1987). 



The owls are generally secretive throughout the year, residing 



