Possible Clues:

• Kiwi's bygone kin
• Extinct ostrich relative
• Extinct relative of the emu
• Sounds as if there might be some more, yet there are no more, like this (3)
• Display in the Auckland Museum
• Ostrich's extinct cousin
• Being extinct, there's no more of them, by the sound of it
• Some bemoan bird that became extinct
• Bird that is no more
• Ted could get water all round the bird that is no more