Archives For pests

Eradicating the great white threat

Department of Conservation —  May 8, 2013 — 1 Comment

By Trish Grant, Communications and Engagement Advisor, Nelson

DOC is renowned for its island pest eradications, now we are leading a pest eradication programme that is focussed on home gardens to wipe out the great white butterfly in Nelson Tasman, which if successful, would be a world first.

The great white butterfly caterpillars.

The caterpillars

The pest butterfly was first found in a Nelson garden in 2010, and has since then been spreading in the city and into nearby Richmond in Tasman. It is a significant pest of brassica plants in numerous parts of the world and is thought to have entered New Zealand as a pupa on an item shipped into Port Nelson.

The aim of the programme is to stop the pest butterfly in its tracks and prevent it spreading to other parts of New Zealand.

With an autumn surge in great white butterfly breeding now underway, around 25 DOC staff are scouring gardens in and around Nelson city searching for the butterfly’s distinctive caterpillars and tiny yellow eggs clustered on host plants. Beating this breeding surge and knocking down the caterpillar numbers is critical to the success of the eradication programme.

The DOC team have initiated a ground-based attempt to eradicate the butterfly in November out of concern at the serious threat it poses to our native cresses; of the 79 species, 57 are at risk of extinction. We need a lot of people on the ground to find and remove all the butterflies, caterpillars and eggs we can to beat the butterfly and stop it becoming a widespread major pest.

The public support has been fantastic. The people of Nelson Tasman have been out looking for and reporting eggs and caterpillars and have been heeding the call to help kill the butterflies to stop them laying eggs.

The programme is due to continue until 2017 and if it succeeds, it will be the first ground-based eradication of the great white butterfly achieved in the world.

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Ulva Island Eradication Update: 21 April 2011

Brent Beaven —  April 21, 2011 — 4 Comments

 
The DOC website has the latest updates on the Ulva Island rat eradication.
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The work on Ulva Island continues to progress, with the work focussed on planning for an eradication option and obtaining the resource consent for this work.

Operational planning

Planning work is progressing well, key decisions have been made about bait storage, loading site, re-fuelling site etc and organisation of these and other aspects of the operation is well on track.

Documentation such as contracts (bait supply, aerial bait spread), operational plan etc are either completed or in final draft phase.

The operational plan has been sent to the Islands Eradication Advisory Group for feedback, (including questions raised by the community such as merits of pre-feeding and best practice for sowing the coast).

IEAG is a team of DOC experts who provide worldwide technical support for island eradication operations. New Zealand leads the world in this field and the meeting was attended by people from far flung places such as French Polynesia, California and the UK, all seeking advice on how to go about eradicating rats from islands.
Calibration of the helicopter buckets has been organised for the last week of April (April 27th). Bucket Calibration is an important step in the eradication process and is carried out in a flat mowed paddock where all bait can be seen and counted. Non-toxic bait is sown through the bucket that is to be used in the operation and the machinery is tweaked to ensure that bait is sown to the correct swath width (i.e. width of strip sown with bait on each pass) and that the correct number of pellets per hectare are sown. Once the correct bait application spread and rate has been achieved the bucket settings are noted so that the toxic bait can be spread correctly on the day.

Biosecurity meeting

As mentioned in the last update, a public meeting will be held at 7.30pm on 28th of April in the Stewart Island Community Centre. This meeting will discuss any and all ideas about possible ways to improve the biosecurity on Ulva Island to further reduce the chances of rats establishing in the future. If you have any ideas, or are simply interested to hear what might be proposed, please come along.

Monitoring

The University of Otago’s bird research group (who monitor robins on Ulva Island every summer) have offered to monitor the effects of the baiting operation and the effects that the rats have had on the birds on Ulva Island. It will be great to have this independent monitoring of the operation.

Trapping stopped

Some confusion seems to have arisen around the reasons as to why we have stopped trapping on Ulva Island.

The long term exisiting biosecurity measures on the island are aimed at preventing a rat population becoming established. In this case, they have failed and a rat population has established. Continuing to run these traps and bait stations will not even now slow the rat population expansion and is therefore considered to be a waste of time. Servicing them has stopped so we can focus efforts on a proper eradication attempt. This has been misinterpreted by some as DOC giving up. The fact is that we are well down the planning track for an aerial eradication attempt.

Regards

Brent

In Animal pests, Southland, Ulva Island , ,
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Stoat on a plate

Tessa Rain —  March 16, 2011 — 1 Comment

The elusive Kapiti Island stoat has been caught. And it’s a… boy! While we can’t be sure this is the only stoat on the island yet, our man at the scene – DOC contractor Hamish Farrell – did do a dance of joy at the discovery.

Hamish Farrell with the dead stoat he found on Kapiti Island

The stoat had spent three months at large, and there were concerns that it would turn out to be a she – which, if pregnant, could have had even more dire implications for the wildlife on the magical island sanctuary. 

A most inventive method was used to lure the two-year-old stoat to its demise: bedding material from a female stoat was put in some of the 160 traps covering the island, sending a message of the possibility of luurve and resulting in the capture. 

DNA testing has confirmed its age and gender, and will hopefully soon tell us whether it’s the same varmint that left faeces behind for our stoat detection dogs to find last year. 

While we will continue monitoring and trapping work for some time yet, with $75,000 spent on the control programme to date, the discovery comes as a great relief to all who love the iconic nature reserve off our coast – and the endangered birds it protects. Stoats beware!

In Animal pests, Wellington/Kapiti , , , ,
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