▁by ▁adult s ▁year - round . ▁ ▁Population ▁There ▁is ▁no ▁data ▁on ▁population ▁dens ities , ▁but ▁like ▁many ▁tiny ▁fal con ets , ▁the ▁total ▁numbers ▁are ▁probably ▁under - record ed . ▁ ▁The ▁overall ▁range ▁extends ▁more ▁than ▁ 1 . 5 ▁million ▁km 2 . ▁ ▁Population ▁assess ments ▁vary ▁from ▁common ▁( in ▁Sum atra ▁and ▁Bor neo ), ▁to ▁fairly ▁common ▁( in ▁Th ailand ), ▁to ▁scar ce ▁( in ▁Java ▁and ▁B ali ). ▁In ▁any ▁case , ▁the ▁population ▁seems ▁to ▁be ▁in ▁the ▁upper ▁tens ▁of ▁thousands , ▁and ▁appears ▁to ▁be ▁toler ant ▁of ▁habitat ▁disturb ance . ▁ ▁References ▁ ▁External ▁links ▁ ▁Historical ▁illustr ations ▁Although ▁most ▁of ▁these ▁illustr ations ▁were ▁published ▁with ▁the ▁name ▁Fal co ▁c ær ules c ens ▁L inn ., ▁Sh ar pe ▁determined ▁that ▁they ▁represent ▁M . ▁fr ing ill arius ▁( D rap iez ). ▁ ▁( C atalog ue ▁Bird s ▁British ▁Museum ▁ 1 8 7 4 , ▁v . ▁ 1 , ▁p . ▁ 3 6 7 ) ▁▁ ▁H ors field ▁( 1 8 2 4 ), ▁Zo ological ▁Research es ▁in ▁Java , ▁plate ▁ 3 5 . ▁Commons , ▁B HL ▁ ▁Tem min ck ▁( 1 8 2 4 ), ▁Plan ches ▁Col ori ées , ▁plate ▁ 9 7 ▁▁ ▁Vie ill ot ▁& ▁O ud art ▁( 1 8 2 5 ), ▁Galerie ▁des ▁O ise aux , ▁plate