▁which ▁give ▁the ▁Tag us ▁est u ary ▁its ▁international ▁importance . ▁The ▁f lock s ▁of ▁winter ing ▁species ▁reach ▁up ▁to ▁about ▁ 1 2 0 , 0 0 0 ▁individuals . ▁The ▁counts ▁regularly ▁carried ▁out ▁in ▁this ▁protected ▁area ▁during ▁the ▁winter ▁show ▁more ▁than ▁ 1 0 , 0 0 0 ▁du cks ▁and ▁ 5 0 , 0 0 0 ▁shore bird s . ▁In ▁the ▁case ▁of ▁the ▁pied ▁av oc et ▁( Rec ur vi ro stra ▁av os etta ), ▁up ▁to ▁ 2 5 % ▁of ▁the ▁population ▁winter ing ▁in ▁Europe ▁has ▁been ▁counted ▁on ▁the ▁Tag us ▁Est u ary . ▁The ▁many ▁other ▁species ▁present ▁att est ▁to ▁the ▁bi ological ▁rich ness ▁and ▁value ▁for ▁nature ▁conservation ▁in ▁this ▁region : ▁the ▁greater ▁fl aming o ▁( P ho en ic opter us ▁rose us ), ▁gre yl ag ▁go ose ▁( An ser ▁an ser ), ▁the ▁d un lin ▁( Cal id ris ▁al p ina ), ▁black - ta iled ▁god w it ▁( L im osa ▁lim osa ), ▁hen ▁har rier ▁( Circ us ▁cy ane us ), ▁o sp rey ▁( P and ion ▁hal ia et us ), ▁bl u eth ro at ▁( L usc ina ▁s vec ica ), ▁common ▁fire c rest ▁( Reg ulus ▁ign ic ap ill us ) ▁and ▁E uras ian ▁p end ul ine ▁tit ▁( Rem iz ▁p end ul inus ) ▁