Due to the northern North Island local extinctions, whiteheads were, until recently, extinct on the mainland of the North Island north of about Hamilton. However, this situation has been rectified by 3 of the above releases in the Hunua Ranges, Waitākere Ranges and on Tiritiri Matangi Island. The Karori and Tiritiri Matangi reintroductions were done independently while the Hunua reintroduction was an Auckland Regional Council initiative. The Auckland Regional Council also played a part in the Waitākere Ranges ""Ark in the Park"" project release – the project is a joint effort being a joint effort between this local government body and the NZ conservation not for profit NGO Forest and Bird.