Lying five and a half kilometers off the western coast of the lower North Island, Kapiti Island is a distinctive landmark of the area: the Kapiti Coast. Important to local Maori, Kapiti is also a significant nature reserve being large (1965ha) and mostly forested. Its conservation values were further increased in 1996, with the eradication of two rat species at which stage Kapiti Island became free of introduced mammals. Kapiti Island acts as a refuge for a number of threatened bird species including takahe, kokako, hihi or stitchbird, little spotted kiwi, red-crowned parakeet or kakariki, brown teal or pateke, weka, kaka, tieke or saddleback, robin, royal spoonbill, as well as more common forest, shore and sea birds.

With a high point of 521m and roughly 10km long and 2km wide, Kapiti rises steeply from the shoreline, particularly on the exposed western face. The eastern side of the Island is divided into distinctive catchments with permanent water courses terminating at the rocky shoreline. After being previously cleared or burnt for farming the majority of the Island is now covered in forest at different stages of regeneration. The most mature and diverse "cloud forest" is found in the central high part of the Island. The only significant area of flat land is a peninsula at the north end of the Island. This land also encloses a shallow lagoon (Okupe) which is now cut off from the sea. Small areas of wetland and grassland persist with much of the Island's vegetation strongly influenced by the weather.

Kapiti Island Nature Reserve is administered by the Department of Conservation which has permanent staff based at Rangatira Point on the eastern side of the Island. A small enclave (14ha) of private land at Waiorua Bay at the north end contains a number of baches, and a small homestay business operates from here.

Brown Teal on Kapiti

Even though Kapiti is a large island the amount of available habitat for brown teal is quite limited. Most of the watercourses run steeply however, some streams and wetland areas provide adequate cover and food sources. Teal have consistently been found around the Okupe lagoon and Waiorua stream at the north end of the Island; at Rangatira around the wetland area; and in the Maraetakaroro Stream and Wharekohu Stream at the south end of the Island. In 1996 teal were captured in the upper Taepiro Stream and the upper two thirds of the Kaiwharawhara Stream is potential teal habitat.

Few historic records of brown teal on Kapiti exist so any birds located may have been stragglers. In 1968, the Wildlife Service released 10 teal, mainly from Mt Bruce where they were captive-reared. The goal was to create a nucleus from which birds could disperse to the mainland. Over the nest three years, 70 young were raised with some birds colonizing mainland sites. However, over time the population decreased probably due to lack of suitable habitat, with only sporadic sightings through to the mid-1990s.

Prior to the rat eradication planned for mid-1996, six teal were located and captured, then held in a purpose -built aviary. Unfortunately due to aggression between the birds, four died leaving one pair which was eventually released in February 1997 following the successful poison operation.

A survey in 1999 using an experienced dog located only one male teal and also a teal-mallard hybrid, both on the Okupe lagoon. In August 2000 teal were recorded from Rangatira and on the Okupe lagoon where the hybrid was again present.

A second series of releases occurred in August 2000 and July 2001. In total, 20 captive-reared teal were released on Kapiti at three locations. Most birds carried transmitters and were closely monitored following release. Up to half the birds had died within the first two months. The cause of death could not be determined for most although two had died of starvation/dehydration. No breeding was recorded during this monitoring period. Intensive monitoring finished in December 2001 but further sightings were recorded by staff including adults seen with juveniles at Rangatira in May 2002 and also at Waiorua in August 2002.

An Island-wide survey using an experienced dog was conducted in May and June of 2002. Nine birds were located including a possible hybrid. No teal were found at Rangatira although it is likely teal were present. More juveniles were seen at the north end of the Island in January 2003. A survey during July 2003, again using an experienced dog located only five birds however once more it is likely that some teal were not located on the survey.

As of September 2004, the population is estimated to be at least 10 birds based on various sightings over the past year. It is assumed that at least one bird is present at Wharekohu at the south end of the Island, and that two pairs are using the Maraetakaroro stream, also at the south end. A pair of teal has been occasionally seen and heard at Rangatira and another pair is readily seen behind the private houses at Waiorua. At least one more bird is likely to be further up the Waiorua Stream. No birds have recently been located on or around the Okupe lagoon.