Opinion by Tony Orman
A newspaper report in late January told of black-backed gulls behaving as predator to other native birds.So what?
Predators in the New Zealand avian ecosystem are nothing new. The native falcon (karearea) preys on small to medium-sized birds, but occasionally takes prey much larger than itself such as black shags, poultry and pheasants. Pukeho can prey on small ducklings. Harrier hawk prey on small birds.
Over millions of years – New Zealand has always had predators. Among extinct birds, the giant Haast Eagle preyed on moa, the adze bills preyed on the chicks of nesting birds, the Eyles harrier preyed on kereru, kokako, kaka and smaller moa up to 40 kgs while small birds were part of the diet of the laughing owl.
In the ocean, kahawai prey on herrings, kingfish prey on kahawai, seals prey on kahawai and snapper prey on crabs and kina in an inter-woven system. From time to time, trout – introduced in the late 19th century – are labelled “invasive predators.” In spring, trout may prey on native whitebait and native shags and native eels prey on juvenile trout.
Haast Eagle preyed on moa
New Zealand has for many decades waged a war against predators. Yet in other countries, predators are recognised as generally beneficial to their prey species. Predators are part of a healthy ecosystem, removing vulnerable prey such as the old, injured, sick or very young, leaving more food for the survival and success of healthy prey species. Predators in effect, control the size of prey populations.
Predators will catch healthy prey when they can, but catching sick or injured animals is much more likely and helps in the formation of healthier prey populations because diseased animals are quickly removed and only the fittest animals survive and are able to reproduce.
But in New Zealand there is a zealous deep prejudice against predators. Predator Free 2050, and Zero Invasive Predators (ZIP), represent an all-out war against predators.
Money Trail
Championing the fight are often prime ministers, central and local government politicians, local bodies, naive unquestioning psuedo-investigative journalists, extreme green groups and even unprincipled “scientists” following the money trail of funding.
Wildlife managers overseas are increasingly regarding predators as an important part of a healthy ecosystem.
For example in 2014, Al S Glen of New Zealand’s Landcare Research and Christopher Dickman of Sydney University co-authored a book on “Carnivores of Australia” and in a chapter “The Importance of Predators” said “to maintain or restore functioning ecosystems, wildlife managers must consider the ecological importance of predators.”
American author Dr.Caroline Fraser writing for the US’s Yale School of the Environment said experts “beginning with aquatic experiments, have amassed considerable evidence of damage done to food chains by predator removal and have extended such studies to land.”
Interference
Examples are many of human interference directly or indirectly into Nature’s food chains resulting in profound consequences. In a classic 1966 experiment, biologist Robert Paine removed the purple seastar Piscaster ochraceus – a voracious mussel feeder from an area of coastline in Washington, US. Their predator gone, mussels exploded in numbers, crowding out biodiverse kelp communities with monoculture. A similar scenario is happening right here in New Zealand with the removal of large snapper and crayfish causing sea urchin (kina) “barrens”.
In New Zealand the fervour and haste which the Department of Conservation and local councils apply with toxins is reckless and fraught with ecological danger.
Large scale poisoning with eco-toxins such as 1080 and brodifacoum may heavily reduce predator numbers initially but with a few short years, the outcome is disastrous. Science There
The science is there to show the resurgence in predator numbers and subsequent damage to the native ecosystem.
Wendy Ruscoe in a study published in Landcare Research’s publication 2008 showed aerial dropping of 1080 will temporarily knock back a rat population but due to the rodent’s amazing reproductive capacity, the surviving rats recover rapidly and within 18 months, their numbers are two to three times greater than before poisoning began. Another study by Landcare scientists Graham Nugent and Peter Sweetapple showed similar rat population explosions following aerial 1080 drops. Stoats whose main prey is rats, then surge in numbers.
Impossible Dream
The concept of being ”predator free” or “zero predators” is not ecological reality, except in limited circumstances on smaller offshore islands and “mainland islands” . Even in islands where predators may have been eliminated e.g. Secretary Island in Fiordland, the success is short-lived and temporary as animals can and do swim from the mainland to recolonise. How else did these predators get there run the first place?
The sad outcome is the gross misuse of public funds and more tragically the profound ecological damage that often occurs in the pursuit of that “Impossible Dream.”
Footnote: Tony Orman has spent a lifetime in the outdoors observing and reading about it and Nature. He has had some two dozen books published, mainly on fishing, deerstalking, conservation and rural life.
Trout are preyed on by native eels and native shags
Scientists – genuine ones – understand the vital role played by predators in ecosystems. They understand the profound impacts that occur when those predators are wiped out. Top article.
Balance is everything in life on Earth.We live continuously with that pesky little voice whispering “MODERATION IN ALL THINGS”it keeps us from an endless list of disastrous traps from soeeding on the roads to glugging a bottle of whisky every day & countless other over indulgencies in stupid land. When rhere is a departure from balance, regardless of the cause that is when a system breaks down.
One of our greatest examples of maintaining balance is when we observe nature. Its default setting is balance, It has no office or department which sends out a memo this shall be so, it is just the way nature IS .i LIKE THE NOTION OF A SPRING, the one thing it strives to do is return to its neutral balanced load setting. Along comes a disruptive force like barbarians from without ,& nature will shrug them off to one side. So like pushing against a spring is futile, it will always return to its balance default setting load.
We in our ignorance of this basic law on too many expansive forays tried to interfere. with balance by the misguidednotions that our spring is not sprung properly.
By wading headlong into the spring fixing business we commit error after error only to arrive after pushing at the spring, right where we started, i e ONE HAPPILY FUNCTIONING LOADED SPRING
Kind of where ignorance & stupidity meet after the dive into the do gooder pool of,”nature needs my help”!
Ecan has made Southern Black Backed Gulls and Australasian Harrier Hawks the villains in the decline in population of the five species of native birds adapted to braided rivers following trail camera evidence from community predator trapping projects.
What is not admitted is that massive abstraction of water from these rivers for irrigation has eliminated many of the islands that protected these ground breeding birds from other predators such as hedgehogs, cats, ferrets, rats, etc.
When the Black Fronted Tern colonies numbered in their thousands, it was the “flock effect” that stopped predation by the larger gulls. The diminished colonies are more much more vulnerable.
The underlying predator is the rapacious water user.
It is necessary. to acknowledge the great environmentalist Bill Benfield in his book, [a must read “At War with Nature,” The concept ofatempting to adjust nature by manipulation poisoning of “unwanted socalled”unwanted “predators”Including the vast array of unwanted sideeffects for example the 1080 poison was developed as an insecticide,killing off & contaminating the food supply of the very species of birds it is meant to protect.
Bill expanded at length on the topic using the push against a spring parallel futility.
We’re used to seeing it overseas .. but everybody in New Zealand has now had the glaring opportunity to bear witness to the fact our own government and its agencies can “go rogue”.
Not only did the previous government act recklessly and irresponsibly in so many ways .. it also committed gross waste of taxpayers’ funds on so many levels.
If they didn’t like the present law .. they changed it. If they found they had broken the law.. they retrospectively changed it, so they hadn’t. They spent more money .. much of which they borrowed .. than any previous government in our country’s history. They got a taste of passing laws “under urgency” and they found they liked it .. so they did so wantonly, whether it was justified or not.
What this tells us is what we should always have known: NOT ALL OUR GOVERNMENT AND ITS AGENCIES TELLS US IS TRUE .. OUR GOVERNMENT AND ITS AGENCIES DO NOT ALWAYS ACT IN OUR COLLECTIVE BEST INTERESTS .. AND WE SHOULD NEVER BLINDLY RELY UPON THEM TO DO SO.
Nowhere has this been more the case, than with Aerial 1080.
Common sense tells us it simply cannot be OK .. to indiscriminately, aerially spread thousands of tonnes .. of a WHO Class 1A ecotoxin .. capable of killing everything that consumes oxygen .. across millions of hectares of otherwise pristine bush and backcountry .. ignoring major Manufacturer’s Warnings, in doing so.
This is exactly the kind of thinking that has contributed to a greater than 60% reduction in global wildlife since 1970 .. and a 75% reduction in insect biomass, over the past 40 years.
Our species perverts and corrupts virtually everything it touches .. as somebody tries to greedily make money.
And what’s worse .. any attempts to fix the disasters we’ve inflicted on our fellow species .. are also perverted and corrupted .. so that somebody can make money out of that, too.
Indeed Stewart. Surely it’s odd that New Zealand can claim over 90 percent of world’s use of 1080, a tiny country uses 90%. Many other countries ban 1080 or strictly limit its use.