Bring back birds
Fiona Eadie makes a case for planting our native flora… on behalf of our native fauna!
Love native birds? Then love the native plants they need, says Fiona Eadie
We love our native birds and want them in our gardens, but do we love with equal passion the plants that provide everything our endemic feathered fauna needs to thrive?
ihave had so many people say to me, “if New Zealand’s native plants were only more interesting, I’d plant more of them.” Which to me translates as, “if our native plants had bigger and more colourful flowers, I would plant more of them.”
But if you are focusing on flashy flowers, you’re missing out. If you take the time to learn about the incredible evolution of our native plants, I guarantee you’ll realise that our natives are more amazing than any exotic you can name. Plus they provide everything our native birds need to thrive.
That’s because our birds and plants evolved together. In fact it is the fault of native birds that our native plants aren’t as floriferous as we would like!
People also have told me they plant exotics because their flowers bring in birds. They seem to too easily forget that our birds and our plants provided all that was needed for each other’s survival before humankind set foot on this land.
We do not need to plant foreign plant species to feed our birds. We simply need to plant more – a lot more – of our own amazing native flora. I am sad to say that there are now more weed species than native plant species found in New Zealand.
The case for native plants
New Zealand’s native birds and the plants found a niche within the ecosystems that existed. Over millennia, and before human settlers arrived here, they existed together and exerted a profound influence on each other’s evolution. Before the first people arrived on the Land of the Long White Cloud, a quarter of our birds had evolved to become land or water dwellers (we have more species of flightless birds – living and extinct – than any other country in the world). But no wonder they became lazy – their only predator was the nowextinct Haast eagle… and who wouldn’t have been scared of that magnificent creature! But the birds that lived here weren‘t all nectar feeders that “reward” flowering plants by pollinating them. In fact only 8 per cent of our native plant species are pollinated by birds – and some of those plants are happy for an insect to do it instead. Many of our native birds – bellbirds, hihi, k¯ak¯a, saddlebacks, t¯u¯i and more – are unusual in that they eat both the nectar and fruit of many plants (and in doing so pollinate the flowers and help spread the seed). So lots of our native plants produce both bird-pollinated flowers and bird-dispersed fruits, rather than just focusing on flowers!
Our native birds do not just need flowering plants – we can get over that idea! They don’t need bread either – forget throwing out the crusts if you want to encourage native birds (although sugar feeders are OK as a support for nectarfeeding birds in winter).
If you don’t plant natives because you don’t like the way they look, I encourage you to look at them again. Many gardeners I meet are inexperienced with our native plants, and have not seen what can be done with them. Others feel they are hard to grow, or simply, do not know them so don’t buy them.
Yet, our native plants have texture, look good, are there in the winter… and yes, some of them offer flowers too!
I am not saying you cannot have your exotic flowering plants; nor that you should have only native plants in your garden. But I am saying that native plants provide our birds with what they need – and support all our other fauna too.
I would love to see gardeners grow more native plants. We are the ones who can bring our country’s flora – and consequently its fauna – back to life. Be sure to ask at your garden centre for any species you cannot find so they can let the nurseries know there is a demand. If they do not know, they will not try to produce them.
Native plants, pollination & evolution
In the evolutionary sense, New Zealand is a young country. There has not really been time for the close associations that can form between a plant and its pollinator – and the often-fancy flowers that follow elsewhere in the world.
Pollination is the first step in the sexual reproductive process in plants, it is the pollen (male part with sperm inside) coming in contact with the stigma of the female part.
Self-pollination is when the egg is fertilised by its own pollen or one from a flower on the same plant. This is great if you wanted to reproduce quickly, like many of our shortlived weed species. But, there is no genetic diversity, so there is less likelihood that the species will have offspring capable of being able to adapt to changes in its environment and/or be resistant to certain pests and diseases.
Cross-pollination on the other hand leads to genetic diversity, the pollen coming from a genetically different plant of the same species. This is all about survival. We think that all plants look identical but an individual species is as variable as we are as
Homo sapiens. We are all so different and so are our plants!
Interestingly it has been shown with kˉakˉabeak that it desires cross-pollination but if it gets to the end of the season and it thinks it has not produced enough seed it will happily self-pollinate. Some weed species have also been shown to undertake self-pollination to colonise a new area and once established move to cross-pollination. How do they know? Ahh, we still know so little about plants!
To ensure cross-pollination plants need a means of transferring the pollen from one plant to another. Some, such as our native beech trees, podocarps, all our grasses and even our coprosmas, are lazy and use the airwaves, letting loose vast quantities. Such plants do not require fancy flowers as there is nothing to attract.
All the other plants use animals. To get the animals to come, the plant needs to provide an incentive, and like most animals food is often the winner on the day. For most it is nectar but for some it will be pollen or even both. In general, the larger the flower the larger the animal undertaking the pollinating. No matter the size of the pollinator it is costing the plant energy to make the product; the bigger the pollinator the greater the demands on the plant. This energy could be being used to grow, defend themselves from pests and diseases, take up nutrients from the soil and more. There is a cost to producing a fancy flower but they will do it for reproduction.
Here, very few native plants produce large flowers because the nectar feeders we have are small. They include our native bees and wasps (both small when compared to relatives elsewhere in the world), moths and our few butterflies. Their proboscises (great word for their straw-like tongues) were of equally small stature. Other nectar-feeding pollinators here are flies, w¯et¯a, bats and of course birds. It used to be thought we had an abnormally high percentage of plant species (about 12 per cent of all flowering species) that had separate male and female flowers; that is, that were dioecious. The theory was it ensured cross-pollination, in turn assuring genetic diversity. But theories come and theories go. A very recent study determined that we do not have a lot of dioecious plants here (in some tropical forests, dioecious plants make up 40 per cent of flowering species). Plus more recent science suggests that only a few plants developed this characteristic once here – perhaps our clematis and rubus species. The rest are now thought to have arrived already with the characteristic. It seems we are not as unique as we thought – but we can cope with that!