Monday, 2 February 2009

NZ pigeons flock to park

By Virginia Winder

Pukekura Park is the New Zealand pigeon capital of the world.
So says Taranaki ornithologist David Medway who has been taking count of the plump birds that swoop-whir overhead like miniature Hercules helicopters.
“We have got more pigeons in New Plymouth city than any other city in New Zealand. I think I’m pretty safe in saying that because there are some cities like Hamilton that don’t have any pigeons and they are busy trying to attract them back.”
The native pigeon (Hemiphaga novaeseelandiae), also known as kereru, has become firmly established in the New Plymouth park and Medway believes there are about 20 birds in residence.
“It’s because of the variety of food that’s provided by the vegetation in the park year round that we are able to maintain such a good population.”
Also, the pigeons’ major foes – possums, ship rats (Rattus rattus) and stoats – are either in such low proportions in the park they don’t pose problems, or simply not there at all.
Perhaps that’s why they don’t venture far from the park boundaries.
During the day some of the pigeons will make flying visits to neighbouring properties, but generally, they don’t go far.
“But they tend to go back into the park – that’s their home base,” says the Friends of Pukekura Park vice-president.
When the Department of Conservation surveyed the park three or four years ago, they discovered the birds stuck close. “They were somewhat surprised at the little movement of pigeons here compared to elsewhere. In other areas, such as Invercargill, where they did their studies, pigeons travel kilometres to get to food sources, but they don’t need to do that here.”
Medway can back this up through his own observations.
“I embarked on a definitive study in Pukekura Park about 10 years ago,” says the retired lawyer.
He visits the park three to four times a week, for a few hours at a time, quietly, methodically, recording his observations of the birdlife.
During his studies, Medway has found that not only is the 52-hectare botanical garden (including the adjoining Brooklands Park) the native pigeon capital; it’s also the tui centre of the world. But that’s another story.
He also notes that pigeons are not easy to spot because after feeding they perch silently in trees for a couple of hours. “You might actually walk under a dozen pigeons and not even know they are there.”
Pigeons are herbivores, but they don’t just go for native plants.
That’s why Pukekura Park, which boasts a wide botanical collection of both home-ground plants and exotics, is such a bird magnet.
Because of this, Medway has had to become an amateur botanist and learn about the plants that lure the birds.
One of his most surprising discoveries is the fact that New Zealand pigeons are partial to magnolias. But not all varieties.
Medway says he’s never seen a pigeon eating a Magnolia grandiflora, or any other evergreen magnolia.
But he has seen them dining on the deciduous, especially sargentiana robusta, stellata and soulangeana magnolias. “The big old historic magnolia on the Brooklands lawn is Magnolia soulangeana.”
“The part the pigeons eat depends on the season. They eat the leaf buds and new leaves, flower buds and flowers of quite a variety of magnolias and magnolia cultivars.”
To make this clear here, the New Zealand pigeon doesn’t like all deciduous magnolia. Just like a person picking from a box of chocolates, the birds have their favourites.
Medway doesn’t know why they prefer some and ignore others.
“My studies show that from about June to October the pigeons in the park are feeding primarily on the foliage and flowers of a variety of different magnolias,” he says.
“That’s pretty unique in New Zealand because I know of nowhere else where pigeons rely to such an extent on magnolia. That’s one thing special about here.”
In fact, he hasn’t found any mention of pigeons feeding on magnolia anywhere else in the New Zealand and so plans to publish a scientific paper on the topic.
The pigeons do eat other plants, he says.
“In the later periods, they also rely on the new leaves of kowhai,” he says.
Bird watching is about being open-minded. “You’re learning all the time.”
But he is a man of pedantic accuracy.
He doesn’t totally dismiss stories of pigeons “drunk” on fermented fruits, or birds too full on berries to fly. But he does wonder if they are urban myths. “In my 50 or so years of bird observations I’ve never seen any of those things. I don’t deny that those things could happen, all I’m saying is I’ve never seen.”
But he has observed many pigeons munching magnolia.
And so, when he says Pukekura Park is the New Zealand pigeon capital, it’s best to believe him.
Caption: A New Zealand pigeon eating a loquat fruit in Pukekura Park. Photo: James Harmsen

NB: This story first appeared in the Taranaki Daily News on January 5, 2009

Freaky Facts about kereru

1) In Northland the New Zealand pigeon has the Maori name kuku or kukupa. Other places it’s known as kereru. On the Chatham Islands the native pigeon is called parea, but that’s a different species altogether, called Hemiphaga chathamensis.
2) The kereru has an important job helping the spread of native trees. Since the moa became extinct, back in the 1500s, the native pigeon is now the only seed disperser with a bill big enough to swallow large fruit, such as those of karaka, tawa and taraire, the DOC website says.
3) A New Zealand pigeon is a big bird. They can measure up to 51cm from tail to beak, and weight 650g.
4) Nest-making is not one of the kereru’s greatest skills. The pigeon throws together a flimsy nest of twigs and lays a single egg, which takes 28 days to hatch. Both parents take turns to sit on the egg.
5) Pigeon chicks are fed on a fruit smoothy mixture that helps them grow fast. This is made from a protein-rich milky secretion that comes from the walls of their parents’ crops, which is mixed fruit pulp. The chicks generally leave the nest after 40 days.