▁colour - marks ▁of ▁this ▁type ▁are ▁considered ▁temporary ▁( the ▁rings ▁deg rade , ▁fade ▁and ▁may ▁be ▁lost ▁or ▁removed ▁by ▁the ▁birds ) ▁and ▁individuals ▁are ▁usually ▁also ▁fitted ▁with ▁a ▁permanent ▁metal ▁ring . ▁ ▁Leg - flags ▁▁ ▁Similar ▁to ▁col oured ▁rings ▁or ▁bands ▁are ▁leg - flags , ▁usually ▁made ▁of ▁Dar vic ▁and ▁used ▁in ▁addition ▁to ▁number ed ▁metal ▁bands . ▁ ▁Although ▁leg - flags ▁may ▁sometimes ▁have ▁individual ▁codes ▁on ▁them , ▁their ▁more ▁usual ▁use ▁is ▁to ▁code ▁for ▁the ▁sites ▁where ▁the ▁birds ▁were ▁band ed ▁in ▁order ▁to ▁el uc id ate ▁their ▁migration ▁routes ▁and ▁st aging ▁areas . ▁ ▁The ▁use ▁of ▁colour - coded ▁leg - flags ▁is ▁part ▁of ▁an ▁international ▁program , ▁origin ated ▁in ▁Australia ▁in ▁ 1 9 9 0 , ▁by ▁the ▁countries ▁of ▁the ▁East ▁Asian ▁- ▁Austral as ian ▁Fly way ▁to ▁identify ▁important ▁areas ▁and ▁routes ▁used ▁by ▁mig rat ory ▁w aders . ▁ ▁Other ▁markers ▁▁ ▁Head ▁and ▁neck ▁markers ▁are ▁very ▁visible , ▁and ▁may ▁be ▁used ▁in ▁species ▁where ▁the ▁legs ▁are ▁not ▁normally ▁visible ▁( such ▁as ▁du cks ▁and ▁ge ese ). ▁Nas al ▁disc s ▁and ▁nas al ▁s add les ▁can ▁be ▁attached ▁to ▁the ▁cul men ▁with ▁a ▁pin ▁loop ed ▁through ▁the ▁nost r ils ▁in ▁birds ▁with ▁per for ate ▁nost r ils . ▁They ▁should ▁not ▁be ▁used ▁if ▁they ▁ob struct ▁breath ing . ▁They