▁the ▁thro at ▁of ▁their ▁parents . Ad ult s ▁go ▁through ▁a ▁synchron ous ▁mou lt ▁of ▁their ▁flight ▁fe athers ▁after ▁the ▁bre eding ▁season , ▁resulting ▁in ▁the ▁loss ▁of ▁flying ▁ability ▁for ▁a ▁brief ▁period . ▁When ▁dist urbed ▁from ▁their ▁per ches ▁during ▁this ▁period , ▁they ▁d ive ▁into ▁the ▁water ▁below ▁and ▁attempt ▁to ▁escape ▁under water . ▁This ▁escape ▁behaviour ▁is ▁also ▁employed ▁by ▁ch icks ▁at ▁the ▁nest . ▁They ▁are ▁very ▁silent ▁except ▁at ▁the ▁nest ▁where ▁they ▁produce ▁gr un ts ▁and ▁cro aks ▁and ▁a ▁dis yll ab ic ▁ch igi - ch igi - ch igi . ▁Ch icks ▁are ▁no isy ▁when ▁begg ing ▁for ▁food . ▁Ad ult s ▁ro ost ▁commun ally ▁in ▁trees ▁close ▁to ▁or ▁over ▁water . ▁ ▁Ch icks , ▁especially ▁those ▁more ▁than ▁half ▁grown ▁are ▁sometimes ▁pre yed ▁on ▁by ▁ra pt ors ▁such ▁as ▁P allas ' s ▁fish ▁e agle ▁( H alia et us ▁le uc ory ph us ). ▁The ▁long ▁sc ap ular ▁fe athers ▁were ▁once ▁popular ▁for ▁use ▁in ▁decor ating ▁h ats . ▁A ▁number ▁of ▁par as ites ▁have ▁been ▁recorded ▁from ▁adult ▁birds ▁including ▁Schw art z it re ma ▁an hing i ▁( T rem at oda ), ▁Pet as iger ▁n icol li , ▁Mes orch is ▁p end ulus , ▁and ▁E chin or h yn ch ota enia ▁tr it est icul ata ▁( C est oda