▁The ▁giant ▁Canada ▁go ose ▁sub species ▁was ▁believed ▁to ▁be ▁ext inct ▁in ▁the ▁ 1 9 5 0 s ▁until , ▁in ▁ 1 9 6 2 , ▁a ▁small ▁f lock ▁was ▁discovered ▁winter ing ▁in ▁Ro chester , ▁Minnesota , ▁by ▁Harold ▁Hans on ▁of ▁the ▁Illinois ▁Natural ▁History ▁Survey . ▁In ▁ 1 9 6 4 , ▁the ▁Northern ▁Pra irie ▁Wild life ▁Research ▁Center ▁was ▁built ▁near ▁Jam est own , ▁North ▁Dak ota . ▁Its ▁first ▁director , ▁Har vey ▁K . ▁Nelson , ▁talked ▁For rest ▁Lee ▁into ▁leaving ▁Minnesota ▁to ▁head ▁the ▁center ' s ▁Canada ▁go ose ▁production ▁and ▁rest oration ▁program . ▁For rest ▁soon ▁had ▁ 6 4 ▁pens ▁with ▁ 6 4 ▁bre eding ▁pairs ▁of ▁screen ed , ▁high - quality ▁birds . ▁The ▁project ▁involved ▁private , ▁state , ▁and ▁federal ▁resources ▁and ▁re lied ▁on ▁the ▁expert ise ▁and ▁co operation ▁of ▁many ▁individuals . ▁By ▁the ▁end ▁of ▁ 1 9 8 1 , ▁more ▁than ▁ 6 , 0 0 0 ▁giant ▁Canada ▁ge ese ▁had ▁been ▁released ▁at ▁ 8 3 ▁sites ▁in ▁ 2 6 ▁count ies ▁in ▁North ▁Dak ota . ▁With ▁improved ▁game ▁laws ▁and ▁habitat ▁recre ation ▁and ▁pres ervation ▁programs , ▁their ▁populations ▁have ▁recovered ▁in ▁most ▁of ▁their ▁range , ▁although ▁some ▁local ▁populations , ▁especially ▁of ▁the ▁sub species ▁B . ▁c . ▁occident alis , ▁may ▁still ▁be ▁decl ining . ▁ ▁In ▁recent ▁years ,