▁may ▁be ▁due ▁to ▁illegal ▁hunting ▁and ▁human ▁disturb ance , ▁with ▁higher ▁male ▁mort ality ▁having ▁been ▁attributed ▁to ▁hunting . ▁ ▁Th re ats ▁and ▁conservation ▁Today , ▁many ▁w ilde be est ▁populations ▁are ▁experien cing ▁rapid ▁decl ines . ▁Over land ▁migration ▁as ▁a ▁bi ological ▁process ▁requires ▁large , ▁connected ▁land sc apes , ▁which ▁are ▁increasing ly ▁difficult ▁to ▁maintain , ▁particularly ▁over ▁the ▁long ▁term , ▁when ▁human ▁dem ands ▁on ▁the ▁landscape ▁comp ete . ▁The ▁most ▁ac ute ▁threat ▁comes ▁from ▁migration ▁bar riers , ▁such ▁as ▁f ences ▁and ▁roads . ▁In ▁one ▁of ▁the ▁more ▁striking ▁examples ▁of ▁the ▁consequences ▁of ▁f ence - building ▁on ▁terrest rial ▁migr ations , ▁B ots wan an ▁authorities ▁placed ▁thousands ▁of ▁kilometres ▁of ▁f ences ▁across ▁the ▁Kal ah ari ▁that ▁prevent ed ▁w ilde be ests ▁from ▁reaching ▁water ing ▁holes ▁and ▁gra zing ▁grounds , ▁resulting ▁in ▁the ▁death s ▁of ▁tens ▁of ▁thousands ▁of ▁individuals , ▁reducing ▁the ▁w ilde be est ▁population ▁to ▁less ▁than ▁ 1 0 % ▁of ▁its ▁previous ▁size . ▁Il legal ▁hunting ▁is ▁a ▁major ▁conservation ▁concern ▁in ▁many ▁areas , ▁along ▁with ▁natural ▁thre ats ▁pos ed ▁by ▁main ▁pred ators ▁( which ▁include ▁l ions , ▁le op ards , ▁African ▁hunting ▁dogs , ▁che et ah s ▁and ▁hy enas ). ▁Where ▁the ▁black ▁and ▁blue ▁w ilde be est ▁share ▁a ▁common ▁range , ▁the ▁two ▁can ▁hy brid ise ,