Myna birds seem to be on the increase in Whanganui but they may not be as problematic as they seem.
Myna birds are backyard bullies squawking and chasing other species around but how much of a problem are they and what should we do about them? Liz Wylie talks to some experts about the noisy invaders in our gardens.
While other bird species hop about on the ground, mynas strut around like they own the place.
Peter Frost of Birds New Zealand described myna as “birds with attitude”.
“They are aggressive towards other birds and they are very territorial,” said Frost.
“There does seem to be more of them around in western parts of Whanganui than there used to be.”
Frost said the birds’ native range is in southern and southeast Asia, in the tropics.
“So it apparently does best in warmer climates,” he said.
“Of course, with global warming, it is quite possible that this constraint may be lifted and we might expect to see the species expand towards what was ‘the cooler south’.
The species known as the common myna was introduced to the South Island of New Zealand in the 1870s by individuals and acclimatisation societies.
Imported from Melbourne where they had been acclimatised it was believed they would survive in a colder climate but they had disappeared in the South Island by the 1890s.
Birds imported by the Wellington Acclimatisation Society in the late 1870s fared better and their progeny spread slowly northwards so that they are now in most parts of the North Island with the largest populations in northernmost areas.
They were not seen north of Waikato until the 1950s and once they reached Northland their numbers increased dramatically.
There are various accounts of reasons why the birds were imported but the most likely explanation would seem to be that as insectivores they would assist farmers by eating insect pests invading their crops.
Northland Regional Council now lists mynas on its pest hub page because of their vast numbers, their tendency to displace native birds, and their impact on the rural economy.
Where they gather in large numbers, the birds feed on crops or fruit causing economic loss to growers and can also affect farmers by eating food meant for livestock.
They have also been known to evict native birds from their nests to inhabit them.
Department of Conservation scientist Tony Beauchamp studies myna populations in Whangārei and Auckland.
Beauchamp has also studied myna populations on Kawau Island in the Hauraki Gulf where he noted that they did not seem to be negatively affecting native bird numbers.
“There are not vast numbers of mynas there and they appear to be co-existing quite well,” he said.
“I know a lot of people don’t like them in their gardens because they see them as noisy and aggressive.”
Beauchamp said while myna birds’ cries are irritating to human ears their language is complex and interesting.
“They have a range of cries and some are quite melodic.
“They like dense foliage and macrocarpa trees are especially attractive to them.”
Although mynas are omnivores, they prefer an insect diet and are often seen along roadsides catching bugs that have been disturbed by traffic.
“Some farmers don’t mind them roosting around their properties because they are good at keeping insect pests in check,” said Beauchamp.
“I was observing a group near a rural property when the farmer came out and asked me what I was doing. When I told him I was checking the myna population in trees along his boundary he told me there were 92 birds and he was spot on.”
Beauchamp said mynas roost in large groups when they are not nesting and will travel 4-6km looking for food during the day.
“The best way to deter them from suburban gardens is to not put food out and to trim tree branches because they don’t like to roost in foliage that lets a lot of light in.”
Beauchamp said even when mynas were present in large numbers in a region they were “not ubiquitous”.
“You won’t see them everywhere - they will find a place that suits them and return to the same area. If they find a good nesting spot they will return there the following year. You might find them in a city but they won’t be in every suburb.”
Horizons Regional Council pest control coordinator Eric Dodd said there had been few complaints about myna birds.
“It is possible that there are more of them in the region but we don’t get a lot of calls about them and we haven’t seen a recent increase,” he said.
“On average we get 800 to 1100 calls about animal pests each year. Birds, in general, don’t feature much and when we do get calls about birds it is usually pigeons and sparrows gathering around silos and stealing grain.”
Dodd said he was not aware of mynas displacing native species from their nests although he had observed them removing the young of other introduced birds such as starlings and swallows from nests to move in.
“They don’t seem to be very successful at raising their own chicks and they nest in some strange places.
“I have seen them nesting in a possum guard on a power pole. They lay a number of eggs but you’ll often see a pair of mynas with only one chick.”
Dodd said if mynas were on the increase in the region they could become a serious concern.
“As with any introduced species, if they were to reach critical mass we would have to look at what to do but really they are not having any noticeable impacts right now.”
The only bird species on Horizons’ animal pest list are rooks, which were introduced to New Zealand shortly before mynas in the 1860s. The birds are capable of stripping crops and ripping up paddocks.
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