Wildlife in Canterbury Wetlands

Ways to attract wetland birds

To encourage birds to your wetland you have to start thinking like them! What ground cover do they like? Where do they normally nest and feed?

Here are a few helpful habitat hints:

• New Zealand scaup like deep, open, clear water.
• Mallards, grey ducks, shoveler, and grey teal favour shallow water around the edges of a pond or lake.
• Paradise shelducks feed on pasture next to wetlands.
• Rails, crakes and pukeko feed and nest around damp areas of vegetation.
• The marsh crake is a secretive birds that feeds in permanently shallow water under cover of dense raupo or flax. They build nests under sheltering sedges among stands of manuka. You would need less than half a hectare of this habitat to support a breeding pair of marsh crake.
• Pied stilts feed on worms and insects in temporary winter pools in paddocks and nest in scattered clumps of rushes.
• All waterfowl need open water to moult in safety, away from predators.
• Tui, waxeyes and bellbirds will feed on flax and kowhai. Kereru will visit fruiting kahikatea (see the wetland planting guide for more information).

So, the bigger and more diverse your wetland, the more diverse your bird life will be.

All the comforts of home

As well as providing the basics (water and shelter) there are a number of "extras" you can provide that will make your wetland a highly desirable home for birds.

• Create gently sloping, irregular shorelines. This allows birds, particularly waders, chicks and ducklings, easy access to and from the water and will extend the belt of reeds and rushes growing around the edge.
• Logs and trees provide perching sites and shelter, however it is important to leave some gaps around the wetland for birds to fly through.
• During the breeding season (September to December for most species) birds are particularly sensitive to disturbance. Grazing or other activities should stop or be significantly reduced at this time.
• Islands or a floating raft with plants growing on it, make safe nesting sites in lakes and ponds. Alternatively Fish and Game can offer advice on nest box designs.
• If your wetland is near a block of native bush, or another wetland, consider linking them by planting a ‘green corridor’ of native plants between them.

Focus on fish

Many of New Zealand’s native freshwater fish live in wetlands for some or all of their lives. Short and longfinned eels, inanga, and giant kokopu are all found in our Canterbury wetlands. These fish also make amazing journeys to and from the sea using a corridor of rivers, streams and drains. This watery pathway must be kept intact for them to complete their lifecycle successfully.

In contrast, the endangered Canterbury mudfish spends all its life in wetlands, even drains or weed-filled creek beds. They have the extraordinary ability to burrow deep into mud or under logs and aestivate (hibernate) for months at a time during dry spells. This means they can occupy temporary wetlands not accessible to other fish.

Wetlands are also home to our native freshwater crab, pea mussel and shrimp.

Whitebait

The juveniles of five of our native fish – banded, giant, and short jawed kokopu, inanga and koaro – are collectively known as ‘whitebait’. Their eggs hatch in autumn and the larvae are washed out to sea. Six months later they make the hazardous return journey as juveniles.

Most of the whitebait fishery catch is inanga. Juvenile kokopu and koaro may migrate over 100 kilometres upstream, even climbing damp rocks alongside steep waterfalls, until they reach sheltered streams and wetland habitats.

Moving right along

Wetlands connected to streams at least 10 cm deep will be accessible to most native freshwater fish. However, long stretches of fast flowing or polluted water, flap gates, or over-hanging culverts act as impassable barriers.

Native fish also need streams with fairly clear water, shading and cover. Muddy water limits their vision and reduces their food supply of aquatic insects. Help fish find your wetland using the tips below.

Simple Solutions

• Set stream culverts low in the stream bed, placed horizontally.
• Rough up the smooth bottom of culverts with cement or rocks to slow water flow.
• Some juvenile fish are able to climb wet surfaces and a flexible corrugated pipe with water trickling through it can be used for fish to travel short distances between two wetland areas.
• Plant overhanging species like flax and sedges for shelter and to keep the water cool.
• A hay bale placed at the head of a ditch entering your wetland will act as a simple silt trap.
• When clearing drains, leave one side or parts of it untouched until plants have grown back.