, ▁and ▁are ▁important ▁for ▁many ▁species ▁of ▁birds ▁that ▁bre ed ▁there ▁each ▁summer . ▁Bre eding ▁species ▁include ▁o sp rey , ▁du cks ▁such ▁as ▁w ige on , ▁sh ov eler ▁and ▁golden ey e , ▁and ▁w aders ▁including ▁red sh ank , ▁sni pe , ▁cur le w ▁and ▁lap wing . ▁The ▁mar sh es ▁also ▁receive ▁winter ▁visitors ▁including ▁gre yl ag ▁ge ese ▁from ▁I cel and ▁and ▁up ▁to ▁ 2 0 0 ▁who oper ▁sw ans . ▁ ▁The ▁national ▁park ▁is ▁class ified ▁as ▁a ▁Category ▁V ▁protected ▁area ▁by ▁the ▁International ▁Union ▁for ▁Conserv ation ▁of ▁Nature , ▁meaning ▁that ▁it ▁is ▁an ▁area ▁in ▁which ▁people ▁have ▁interact ed ▁with ▁the ▁landscape ▁for ▁many ▁years , ▁and ▁which ▁is ▁managed ▁to ▁sust ain ▁the ▁habit ats ▁and ▁landscape ▁that ▁have ▁resulted ▁from ▁this ▁interaction . ▁The ▁IU CN ▁defines ▁" National ▁Park s " ▁as ▁areas ▁conform ing ▁with ▁Category ▁II ▁of ▁its ▁classification ▁system ▁( q . v . ▁the ▁Hard anger vid da ▁National ▁Park ), ▁however ▁Scotland ▁in ▁general ▁la cks ▁such ▁areas , ▁as ▁thousands ▁of ▁years ▁of ▁human ▁activity , ▁including ▁agricult ure , ▁historical ▁def or est ation , ▁over gra zing ▁by ▁sheep ▁and ▁de er , ▁and ▁extensive ▁ 2 0 th ▁century ▁aff or est ation ▁with ▁introduced ▁tree ▁species ▁( part icular ly ▁con if ers ), ▁have ▁resulted ▁in ▁land sc apes ▁which ▁are ▁best ▁described ▁as ▁semi