▁the ▁Vienna ▁spec imen , ▁and ▁sharp ▁and ▁buried ▁in ▁the ▁fe athers ▁of ▁the ▁Liverpool ▁spec imen . ▁This ▁feature ▁is ▁variable ▁among ▁other ▁kinds ▁of ▁sw am phen . ▁The ▁soft ness ▁of ▁the ▁rect rices ▁( tail ▁fe athers ) ▁and ▁the ▁lengths ▁of ▁the ▁secondary ▁and ▁wing ▁cover t ▁fe athers ▁relative ▁to ▁the ▁primary ▁fe athers ▁appear ▁to ▁have ▁been ▁intermediate ▁between ▁those ▁of ▁the ▁pur ple ▁sw am phen ▁and ▁the ▁tak ah ē . ▁ ▁Although ▁the ▁known ▁sk ins ▁are ▁mostly ▁white , ▁contemporary ▁illustr ations ▁dep ict ▁some ▁blue ▁individuals ; ▁others ▁had ▁a ▁mixture ▁of ▁white ▁and ▁blue ▁fe athers . ▁Their ▁legs ▁were ▁red ▁or ▁yellow , ▁but ▁the ▁latter ▁colour ▁may ▁be ▁present ▁only ▁on ▁d ried ▁spec im ens . ▁The ▁bill ▁and ▁front al ▁shield ▁were ▁red , ▁and ▁the ▁ir is ▁was ▁red ▁or ▁brown . ▁According ▁to ▁notes ▁written ▁on ▁an ▁illustr ation ▁by ▁an ▁unknown ▁artist ▁( in ▁the ▁collection ▁of ▁the ▁artist ▁Thomas ▁Wat ling , ▁in ac cur ately ▁dated ▁ 1 7 9 2 ), ▁the ▁ch icks ▁were ▁black ▁and ▁became ▁bl u ish - gre y ▁and ▁then ▁white ▁as ▁they ▁m ature d . ▁The ▁Vienna ▁spec imen ▁is ▁pure ▁white , ▁but ▁the ▁Liverpool ▁spec imen ▁has ▁yellow ish ▁ref lections ▁on ▁its ▁neck ▁and ▁breast , ▁black ish - blue ▁fe athers ▁spe ck led ▁on ▁the ▁head ▁( con cent r ated ▁near ▁the ▁upper ▁surface ▁of