▁n ests ▁of ▁all ▁species ▁were ▁in ▁cover ▁mi xt ures ▁rather ▁than ▁pure ▁stands ." ▁ ▁Hab itat ▁assess ment ▁Research ▁conducted ▁before ▁ 1 9 5 0 ▁on ▁sharp - ta iled ▁gr ouse ▁habitat ▁assess ment ▁was ▁done ▁vis ually . ▁ ▁H amer st rom ▁( 1 9 3 9 ) ▁reported ▁sparse ▁veget ation ▁was ▁s eld om ▁selected ▁for ▁nest ing ▁due ▁to ▁lack ▁of ▁ade qu ate ▁cover . ▁Hab itat ▁general izations ▁were ▁formed ▁based ▁on ▁the ▁number ▁of ▁individuals ▁found ▁at ▁a ▁given ▁local . ▁These ▁assumptions ▁were ▁if ▁more ▁birds ▁were ▁present ▁at ▁one ▁location ▁and ▁less ▁at ▁another , ▁then ▁the ▁first ▁must ▁be ▁the ▁better ▁habitat . ▁H amer st rom ▁( 1 9 6 3 ) ▁observed ▁ 1 1 9 ▁of ▁ 2 0 7 ▁( 5 7 %) ▁gr ouse ▁bro ods ▁frequent ing ▁sav ann ah ▁style ▁habitat . ▁He ▁concluded ▁that ▁the ▁sav ann ah ▁style ▁habitat ▁was ▁the ▁habitat ▁needed ▁for ▁best ▁management . ▁As ▁the ▁research ▁on ▁habitat ▁for ▁gr ouse ▁species ▁m ature d , ▁so ▁did ▁the ▁techniques ▁used ▁for ▁assess ment . ▁Cover ▁bo ards ▁and ▁Rob el ▁pol es ▁were ▁developed ▁to ▁measure ▁visual ▁obst ruction ▁( VO ) ▁and ▁create ▁habitat ▁indices . ▁Cover ▁bo ards ▁were ▁developed ▁as ▁early ▁as ▁ 1 9 3 8 ▁by ▁W ight ▁( 1 9 3 8 ) ▁to ▁study ▁white - ta iled ▁de er ▁habitat . ▁W ight ’ s