A "ring of steel" has been set up to protect a young Wellington family.
But it is a family with a difference - the saddleback bird nest could be the first found outside the safety of a mainland sanctuary in more than 100 years.
The nest of two rare saddleback chicks was discovered two weeks ago in Polhill Gully behind Aro Valley by Zealandia conservation officer Matu Booth when he was out looking for kakariki.
Polhill Restoration Project's Marc Slade said the nest had since been surrounded by predator traps and volunteers were keeping watch. "We have put in a ring of steel around the nest."
The nest was already close to one stoat trap and two more had been added, along with six rat traps. "For a bird like that to be breeding in an unprotected area is a once-in-a-century experience."
Wellington City Council urban ecology team leader Myfanwy Emeny described the saddleback as an attractive bird with tan feathers across its back that looked like a saddle, and red wattles on each side of its beak. As it spent a lot of time close to the ground and was not a strong flier, it was vulnerable to predators.
The "danger time" was coming for the young birds, when they left the nest and spent about 26 days on the ground waiting to be fed and following their parents around. She urged people visiting the reserve to keep dogs on a lead.
Until recently, saddlebacks were extinct on the mainland for more than 100 years. They were introduced to the mainland in 2002 at Zealandia. Since then they had been introduced elsewhere on the mainland but never outside fenced sanctuaries.
Raewyn Empson, from Zealandia, said their discovery outside the sanctuary's fence was a reflection of their successful introduction to Zealandia. "If this nest is successful, this may well be the first outside the safety of an exclusion fence in over 100 years."
The Department of Conservation said saddlebacks were once widespread but forest clearance and introduced predators led to their decline.
