Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search


No 'black and white' case against magpies

No 'black and white' case against magpies

Results from a four-year study suggest that while magpies do chase and sometimes kill other birds, they are far less of a threat to native species than pest mammals. As a consequence, many regional councils are unlikely to establish large ongoing magpie control programmes.

Landcare Research and Waikato University have been examining the effects of magpies on rural bird populations in five regions: Northland / Auckland, Waikato, Bay of Plenty, Wellington and Southland. In each area, regional councils established two study blocks covering nine hundred hectares each: one where magpies were killed, and another where they were not killed. All types of birds were counted in all blocks in 1999 before magpie control began, with further counts in the next 3 years.

Landcare Research pest ecologist John Innes says by the end of the study, magpie populations in the kill blocks had decreased by 60 to 80%. As a result, there was a 130% increase in the very low numbers of kereru that were originally counted, and a weaker and more variable result for tui. Magpie control also caused definite but unspectacular increases in sightings of five introduced birds: songthrush, myna, starling, blackbird and skylark.

However, Mr Innes says these increased sightings do not necessarily mean there were more of these birds.

"At a farm scale, magpies seem to control the conspicuousness of the birds, rather than their abundance. It is likely that the number of birds was relatively unchanged, but individual birds were seen more often.

"Breeding pairs of magpies can be very territorial and will chase and occasionally kill other birds, probably to keep them away from food sources. These birds then have to seek food farther afield.

"If farmers want native birds to have access to particular places such as their gardens, controlling magpies around the gardens is probably worthwhile. With magpies in the garden, rural dwellers will see native birds less often, although this does not mean there are fewer native birds in total.

"However, when you remove territorial magpie pairs, you get constant re-invasion by previously non-territorial birds. It is an endless and expensive battle."

Mr Innes says based on the results of the study, the five participating councils will not invest significant amounts in large-scale magpie control.

"It is better to concentrate on controlling mammal pests. They are the ones that attack nests, and limit numbers of native birds. Magpies are clearly unlikely to eradicate another bird species from the wider landscape.

"Magpies are scapegoats, in a sense. They are conspicuous, noisy and active in the daytime, while mammals such as ship rats, possums, cats and stoats are secretive, nocturnal, silent and tree dwelling. Therefore, people do not see what mammals do. Inevitably, the role of mammals tends to be underrated, and magpies exaggerated.

"Pest mammal control increases tui and kereru populations in native forests. Now we are keen to try a new experimental mammal control operation with and without magpies, based in rural areas rather than large native forests, to get an even clearer picture."

© Scoop Media

Business Headlines | Sci-Tech Headlines


I Sing The Highway Electric: Charge Net NZ To Connect New Zealand

BMW is turning Middle Earth electric after today announcing a substantial contribution to the charging network Charge Net NZ. This landmark partnership will enable Kiwis to drive their electric vehicles (EVs) right across New Zealand through the installation of a fast charging highway stretching from Kaitaia to Invercargill. More>>


Watch This Space: Mahia Rocket Lab Launch Site Officially Opened

Economic Development Minster Steven Joyce today opened New Zealand’s first orbital launch site, Rocket Lab Launch Complex 1, on the Mahia Peninsula on the North Island’s east coast. More>>


Marketing Rocks!
Ig Nobel Award Winners Assess The Personality Of Rocks

A Massey University marketing lecturer has received the 2016 Ig Nobel Prize for economics for a research project that asked university students to describe the “brand personalities” of three rocks. More>>


Nurofen Promotion: Reckitt Benckiser To Plead Guilty To Misleading Ads

Reckitt Benckiser (New Zealand) intends to plead guilty to charges of misleading consumers over the way it promoted a range of Nurofen products, the Commerce Commission says. More>>


Half A Billion Accounts, Including Xtra: Yahoo Confirms Huge Data Breach

The account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (the vast majority with bcrypt) and, in some cases, encrypted or unencrypted security questions and answers. More>>


Rural Branches: Westpac To Close 19 Branches, ANZ Looks At 7

Westpac confirms it will close nineteen branches across the country; ANZ closes its Ngaruawahia branch and is consulting on plans to close six more branches; The bank workers union says many of its members are nervous about their futures and asking ... More>>

Interest Rates: RBNZ's Wheeler Keeps OCR At 2%

Reserve Bank governor Graeme Wheeler kept the official cash rate at 2 percent and said more easing will be needed to get inflation back within the target band. More>>


Get More From Scoop

Search Scoop  
Powered by Vodafone
NZ independent news