Family: طيور بترلThe procellariids are the main group of medium-sized 'true petrels', characterised by united nostrils with a medium septum, and a long outer functional primary.
===Grebes===Order: PodicipediformesFamily: Podicipedidae===Shearwaters and petrels===Order: ProcellariiformesFamily: ProcellariidaeThe procellariids are the main group of medium-sized "true petrels", characterised by united nostrils with medium septum and a long outer functional primary.