ly ▁sh aped ▁be aks ▁are ▁adapted ▁to ▁separate ▁mud ▁and ▁s ilt ▁from ▁the ▁food ▁they ▁consume ▁and , ▁uniqu ely , ▁are ▁used ▁ups ide - down . ▁ ▁Gre ater ▁Fl aming o , ▁Pho en ic opter us ▁rose us ▁ ▁She ar w aters ▁and ▁pet rel s ▁Order : ▁Pro cell ari iformes Family : ▁Pro cell ari idae ▁ ▁The ▁pro cell ari ids ▁are ▁the ▁main ▁group ▁of ▁medium - s ized ▁" true ▁pet rel s ", ▁character ised ▁by ▁un ited ▁nost r ils ▁with ▁medium ▁sept um ▁and ▁a ▁long ▁outer ▁functional ▁primary . ▁ ▁Sc op oli ' s ▁she ar water , ▁Cal on ect ris ▁di om ede a ▁Great ▁she ar water , ▁Ar den na ▁gra vis ▁( A ) ▁So oty ▁she ar water , ▁Ar den na ▁gr ise us ▁Y el kou an ▁she ar water , ▁P uff inus ▁y el kou an ▁ ▁Northern ▁storm ▁pet rel s ▁Order : ▁Pro cell ari iformes Family : ▁H ydro bat idae ▁ ▁The ▁northern ▁storm ▁pet rel s ▁are ▁the ▁smallest ▁se ab ird s , ▁relatives ▁of ▁the ▁pet rel s , ▁feed ing ▁on ▁pl ank ton ic ▁cr ust ace ans ▁and ▁small ▁fish ▁picked ▁from ▁the ▁surface , ▁typically ▁while ▁hover ing . ▁The ▁flight ▁is ▁flutter ing ▁and ▁sometimes ▁bat - like . ▁ ▁European ▁storm ▁pet rel , ▁H ydro b ates ▁pel ag icus ▁( A