inct ▁species ▁are ▁known ▁to ▁be , ▁or ▁are ▁sus pected ▁of ▁having ▁been , ▁flight less ▁( based ▁on ▁observations ▁of ▁living ▁birds ▁and ▁the ▁size ▁of ▁their ▁stern a ); ▁along ▁with ▁the ▁long - leg ged ▁b un ting ▁from ▁T ener ife , ▁one ▁of ▁the ▁Can ary ▁Islands , ▁they ▁are ▁the ▁only ▁passer ines ▁known ▁to ▁have ▁lost ▁the ▁ability ▁to ▁fly . ▁Of ▁the ▁species ▁for ▁which ▁the ▁pl um age ▁is ▁known , ▁they ▁are ▁d rab - col oured ▁birds ▁with ▁brown - green ▁pl um age . ▁ ▁They ▁form ▁mon og am ous ▁pair ▁b onds ▁to ▁raise ▁their ▁young , ▁lay ing ▁their ▁eggs ▁in ▁small ▁n ests ▁in ▁trees ▁or ▁amongst ▁rocks . ▁They ▁are ▁di urn al ▁and ▁like ▁all ▁New ▁Zealand ▁passer ines , ▁for ▁the ▁most ▁part , ▁are ▁sed ent ary . ▁ ▁New ▁Zealand ▁wr ens , ▁like ▁many ▁New ▁Zealand ▁birds , ▁suffered ▁several ▁ext in ctions ▁after ▁the ▁arrival ▁of ▁humans ▁in ▁New ▁Zealand . ▁Two ▁species ▁became ▁ext inct ▁after ▁the ▁arrival ▁of ▁the ▁M ā ori ▁and ▁the ▁Pol yn esian ▁rat ▁and ▁are ▁known ▁today ▁only ▁from ▁foss il ▁remains ; ▁a ▁third , ▁Ly all ' s ▁w ren , ▁became ▁ext inct ▁on ▁the ▁main ▁islands , ▁surv iving ▁only ▁as ▁a ▁re lict ▁population ▁on ▁Steph ens ▁Island ▁in ▁the ▁Cook ▁Stra it . ▁This ▁species ▁and ▁the ▁bush w ren ▁became ▁ext inct ▁after ▁the ▁arrival