Me pēnei te tohu i te whārangi:
Gordon Ell, 'Ngā whakaahua, ngā rauemi katoa', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/mi/birdwatching/media (accessed 29 September 2023)
He kōrero nā Gordon Ell, i tāngia i te 24 Sep 2007, reviewed & revised 17 Feb 2015