Ulva Island Eradication Update: 21 April 2011

Brent Beaven —  21/04/2011

The DOC website has the latest updates on the Ulva Island rat eradication.

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.


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.



4 responses to Ulva Island Eradication Update: 21 April 2011


    Could you put the updated list of poison found in fish etc please, also the bird numbers on Ulva Island now and the bird numbers prior to the drop?

    Which species has suffered the highest loss?

    Did you identify any kiwi in the area?

    Were you able to find the 1 or 2 deer present on the island prior to the drop?

    What about the current status of rats?


    Brent, please do not “jump the gun” there are submissions against the DoC position and they should be as respected as those supporting the DoC position. We do still live in a democracy.
    There are very genuine concerns for the high expected losses that DoC has identified as likely to occur with a 14kg per hectare of brodifacoum poison aerial drop. These losses represent both rare and endangered and more prolific native birdlife and some lizards also and this is not acceptable to all NZers by any means.Those opposed expect even wider kills of natives including seals and seabirds and fish. It is not reasonable for you to proceed further without first respecting the opposition view point.


      Hi Mary. Thanks for taking the time to talk to us about your concerns. Brent is in the field for the week. I’ll get him to get back to you as soon as he is able – probably next week some time.

      Brent Beaven 09/05/2011 at 4:35 pm

      Hi Mary
      We are working though this very carefully – there is no gun jumping allowed in situations like this. I do respect the oppositions viewpoint, but we have based the decision to proceed with an aerial application on science and the best advice in the world. We have taken advice from the world experts in rat eradications and also met with our community and key stakeholders where we have had 90% of people supportive of our proposed actions. Nevertheless, we have a consent hearing with Environment Southland on 19th May to see if we can further address the concerns that you have outlined. I hope we can, as the consent hearing is costing tens of thousands of dollars that could have been put toward improved biosecurity for Ulva Island.
      I also have very genuine concerns for the expected losses on Ulva Island, but I disagree that they are “high”. If we dont use an aerial spread of bait to eradicate rats but instead try another technique then we drastically reduce the chances of achieving eradication, we extend the operational timing by at least a year and we put at risk all of the species on Ulva Island. If we conduct an aerial operation, then we will lose a small percentage of some birds species, but in tha main, these will be replaced within one breeding season and Ulva will be back to its thriving rat free best.
      Yes, there will be some negative effects, but the evidence of previous eradications show us that these negatives are far, far outweighed by getting rid of the rats. It is really a simple choice between having rats or birds. I vote for birds.