e) Roosting cover for sleeping. 
     
     Each species will have specific needs. 
     
    

    
     To create cavities for nest excavators you should retain both case 
     
     hardened (dead trees with the outside hardened and the inside rotten) and 
     
     soft snags (those which are soft on the outside and solid on the inside). 
     
     For the purposes of bird nesting, a snag must be a minimum of 10 cm (4") at 
     
     chest height and 1.8 m (6' in height). A minimum of five to six per acre is 
     
     advisable for nesting purposes. These should be evenly distributed across 
     
     the area and they should vary in size. Where none are available, snags can 
     
     be created by girdling live trees. When trees are to be girdled the trees 
     
     should be picked to allow varying life of the snag (e.g., poplars and white 
     
     birch will rapidly evolve into a snag after girdling but they will also 
     
     decompose quickly, maples will slowly evolve as snags but remain useful for 
     
     extended periods). 
     
    

    
     Where no trees appropriate for snag creation are available or where the 
     
     owner wishes to conveniently observe cavity users, the erection of nest boxes 
     
     may suffice. Woodworking for Wildlife has an excellent series of designs. 
     
     Nest boxes should be cleaned each fall unless they have been occupied by 
     
     squirrels. 
     
    

    
     Ground shelter areas for food Storage or nesting are appropriate in wet 
     
     areas. They can be fabricated using branches, rocks, chimney liners, or 
     
     other materials. In all cases, care should be taken that the shelter is 
     
     built on a rise of ground, not in a hollow, as this will help to keep them 
     
     dry. If tar paper is used to roof over a few cavities, it will further 
     
     protect the animals using it from rain and snow. The structure should.allow 
     
     entrance from several directions, at least one of which offers aerial cover. 
     
    

    
     Escape_cover can be retained in young white spruce stands by the 
     
     retention of dense young unthinned patches approximately four to five meters 
     
     square. In open ares the interplanting of conifers in small patches will 
     
     allow cover to be created. Wild rose patches may be created or enhanced for 
     
     both food protection and escape cover. 
     
    

    
     Subnivian (under snow) cover can be enhanced by creating bridge trees 
     
     (stems supported off the ground by branches) which develop runways on the 
     
     underside of the stem and by planting shelter belts to cause snow entrapment. 
     
     When using logs close to the ground, put them across the slope so that summer 
     
     runways are also created. 
     
    

    
     The retention of small numbers of dense crowded conifers in deciduous 
     
     stands or the planting of shelter belts will provide roosting habitat. 
     
    
   
   
    
     Perches: . 
     
    

    
     Many of the birds use perches either in the defense of territory or as 
     
     observation points for capturing food; e.g., flycatchers. They also play an 
     
     important part in the defense of red squirrel territories. 
     
    
   
   
    
     Grit: 
     
     The distribution of grit or exposure of the ground may be helpful to 
     
     certain species of birds, particularly in winter. 
     
    
   
   
    
     Display Areas: 
     
    

    
     Certain species of birds require special areas for their courtship 
     
     rituals. The woodcock uses an area of very short or sparse grass in some 
     
     aspects of courtship and the ruffed grouse uses drumming logs. 
     
    
   
   
    
     -12..