on ▁lot or ), ▁red ▁fo xes ▁( V ul pes ▁vul pes ), ▁large ▁g ull s ▁( Lar us ▁species ), ▁common ▁ra vens ▁( Cor v us ▁cor ax ), ▁American ▁c rows ▁( Cor v us ▁bra ch yr h yn chos ), ▁car r ion ▁c rows ▁( in ▁Europe , ▁Cor v us ▁cor one ) ▁and ▁both ▁brown ▁( U rs us ▁ar ct os ) ▁and ▁American ▁black ▁be ars ▁( U rs us ▁amer ican us ). C amp bell , ▁R . ▁W ., ▁N . ▁K . ▁Da we , ▁I . ▁Mc Tag gart - C owan , ▁J . ▁M . ▁Cooper , ▁G . ▁W . ▁Kaiser , ▁and ▁M . ▁C . ▁E . ▁Mc N all . ▁( 1 9 9 0 ). ▁The ▁birds ▁of ▁British ▁Columbia , ▁Vol . ▁ 1 : ▁introduction ▁and ▁lo ons ▁through ▁water f ow l . ▁R . ▁Br . ▁Columbia ▁Mus . ▁Victoria . Bar ry , ▁T . ▁W . ▁( 1 9 6 7 ). ▁The ▁ge ese ▁of ▁the ▁Anderson ▁River ▁delta , ▁North west ▁Territ ories . ▁Ph d ▁Th esis . ▁Un iv . ▁of ▁Al berta , ▁Ed mont on . ▁ ▁Once ▁they ▁reach ▁ad ul th ood , ▁due ▁to ▁their ▁large ▁size ▁and ▁often ▁ag gress ive ▁behavior , ▁Canada ▁ge ese ▁are ▁rarely ▁pre yed ▁on , ▁although ▁prior ▁injury ▁may ▁make ▁them ▁more ▁vulner able ▁to ▁natural