Reports from Districts Show that Opossum Damage to Bush and Birds Is Appalling

Forest and Bird, Issue 173, 1 August 1969, Page 3

Reports from Districts Show that Opossum Damage to Bush and Birds Is Appalling

RECENTLY the Society was requested by the Nature Conservation Council to offer comment on the effect the opossum was having on our native forests and birds. We knew, of course, the damage these introduced marsupials were doing to our bush and birds, but to obtain up-to-date information we invited our sections to supply evidence. Some of the evidence sent in was almost unbelievable; in fact we had to request confirmation of some reports so that there could be no possibility of mistake.

OPOSSUMS have now spread to the Far North and unless some practical remedy can be found of dealing with these destructive pests, it seems that the lovely pohutukawa coastal fringes are doomed to extinction.

In New Zealand opossums appear to be omnivorous, but they prefer certain tree species which they will concentrate on until the trees die; fuchsias and five-fingers appear

to be particularly vulnerable. There is evidence that opossums take bird eggs, but whether or not this is a general habit, it is quite certain that they do destroy nests and compete, vigorously for the native birds’ food supplies.

Goats, deer, and other browsing animals aid the spread of opossums by making tracks which the opossums use. Generally the pest does not care for dense, wet undergrowth.

One of the most disturbing features of opossum control is the danger caused by ground traps to our flightless birds, especially the kiwi. Having its leg caught in a trap is often fatal to the kiwi. , Following are extracts from a few of the reports submitted. The photographs were sent in by Mr Devonshire, of Whangarei,. who has assured us that the damage to the pohutukawa groves illustrated is certainly due to opossums. Hamilton: Opossums destroyed a crop of swedes in the Te Whetu district. Poison that was laid resulted in 1,700 opossums being taken in the first night ! It was expected this number would be doubled in the next few nights. In 80 acres of pines planted near native bush at Ngatira opossums took the centres out of most of the small pines. Poison was laid and on the first night 370 opossums were taken.

Ruatahuna: Berries such as tawa are a valuable food for pigeons, enabling them to build up stamina for winter. Reports state that opossums killed at Ruatahuna had their stomachs filled with tawa berries. Ruahine (east of Dannevirke): Whole hillsides once covered with kamahi 20 to 30 ft high are now a mass of dead and rotting trees. Nearly all the fuchsias are also dead. When the roots of these dead trees rot erosion is likely to be serious. In the hills east of Napier: No fuchsias have been left. alive and the five-fingers have been stripped. Whangarei: Orchards have a terrible time. Young trees are broken and often ruined ; lemons are left ruined, with skins eaten. No fruit trees, except tamarillos and perhaps guavas are immune, from attack. Large groves of pbhutukawas are killed in parts away from settled areas. Puriri bark is eaten and kohekohe, karaka, and taraire fruit disappears. Puketitiri, Hawke’s Bay: In most parts of the district, particularly in sheltered gullies and gorges, almost all the palatable native shrub species have been killed by opossums during the last 3 years. Damage to fodder crops and home orchards and gardens is severe. A most disturbing feature of the opossum invasion is that among the first native trees to be defoliated and killed are those species which produce the best crops and nectar for native birds. Nelson: During the past half-century there have been tremendous changes in the flora of the back country southward from Farewell Spit through the action of introduced animals. The No. 1 enemy of our native flora now is clearly the opossum. Pokororo (Mt. Arthur Range-Leslie Tableland area): Over the past 10 years the opossum population has trebled, as shown by the obvious signs of droppings, tracks, the destruction of big rata trees, and the damage to whiteywood and fivefinger. Hastings: In Blowhard Bush, on less than 100 acres of vegetation, one poisoning killed 600 opossums, and this was only a moderate

part of the vermin there. They have been killing off fuchsias and five-fingers by defoliation. The country is swarming with them, and they are now eating the pastures alongside any bush. They are the greatest menace to bush and birds. One of our members driving through the Urewera at night killed 10 of them on the road, and that was not intentional. Canterbury: Forty opossums were counted at night feeding on a chou moellier crop. Some years ago a Peraki farmer had several acres of winter turnips destroyed by hundreds of opossums living in an adjacent reserve. Steps have since been taken to deal with these. Wellington (Otari Native Plant Museum): About 4 years ago a university student wrote his thesis on the “Feeding Habits of the Opossum in the Otari Native Plant Museum”. In this he related that 24 traps were set regularly for a period of 3 to 4 months and that rarely fewer than 20 of these traps contained an opossum the following morning. This student estimated that at that time the opossums in the bush could be reckoned not in hundreds but in thousands. Owing to trapping since, the opossum population has been considerably reduced, though damage from these pests is still much in evidence. Debris on bush paths is most readily seen where five-finger grows nearby, and the dead tops of such trees as hinau and whiteywood are seen easily on south-facing slopes. The primary cause of death of many of these trees is considered to be defoliation during

attacks by the opossum. Over the past 3 years the slow death of a group of pohutukawa trees has resulted from defoliation by opossums.

Two New Reserves at Whakatane

TWO new reserves, one scenic and the other historic, have been established at Whakatane. The new scenic reserve, Kohi Point, will include 380 acres of the Whakatane Headland and will be administered by the Whakatane County Council. The 12-acre historic reserve, to be named Kapu Te Rangi, will be controlled by the local borough council. An ancient pa site whose earthworks are still prominent is contained in the historic reserve. This is reputed to be the first pa site of the Maori voyager Toi, and the fortified

pa is thought to have come into existence about the fifteenth century, after the arrival of the Mataatua canoe, which came to Whakatane in the mid-fourteenth century. Earth at the pa site is said to have been brought in baskets from “Hawaiki”, and in a ceremony in 1940 selected Maoris re-enacted the planting of the first kumaras brought to the spot by the Mataatua canoe. The Kohi Point Scenic Reserve is the most prominent feature on the coastline near Whakatane and includes the beautiful Otarawairere Bay.