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Citizen Science preliminary Chew Card Results

Once again, our preliminary results for our Kaipātiki wide pest animal survey are in. Thank you to all the regular volunteers and families who made it possible, and also a welcome to new volunteers who tried walking the lines for the first time this year.

With all the things going WRONG in 2020, perhaps we have something positive here…the maps are reducing in the number of red ‘hot spots’.

However - It is worth noting down that a number of lines were not surveyed this year, largely due to closures for maintenance work or kauri dieback precautionary measures. We will rely on the great monitoring work the council does via Wildlands consultants to get a picture of how these closed reserves are faring from pest animal populations.

These are also not the full results, we will report back with more detail at a later date.

Below are the series of 2020 chew card result maps based on the number of cards chewed by any particular animal. We measure pests with ‘relative abundance’ which is a percentage composition of an organism of a particular kind (i.e mouse or rat), relative to the total number of organisms in the area. Essentially - the lower the relative abundance the better - i.e closer to zero.

Relative abundance colour key:

  • No browse (green), no cards on this line were chewed

  • Low browse (blue), 10 – 20% of cards chewed

  • Moderate browse (brown), >20 – 60% of cards chewed

  • High browse (red), >60% of cards chewed

As you can see above, a number of reserves this year did not track rats or mice which is great news. On the other end of the scale, we can see a few hot spots for rat activity - particularly within the eastern end of Bayview South Coast (actually Witheford Reserve), Chelsea heritage park close to colonial road and the very western line at Le Roys Bush - closer to the shops. Rangatira, Castleton Reid and Tamahere reserves also turn up as hot spots for both kinds of rodents.

Chew marks categorised as ‘Other’ can include mustelids like stoat or weasel, hedgehog as well as other dogs, cats or anything ‘other’ that can leave a mark on a chew card - including possible nail marks. Mustelids and hedgehog in particularly can hoover up many kinds of invertebrates, eggs and birds - something be very vigilant about if they show up on the cards. No lines this year had over 60% of their cards chewed by one of these animals, however moderate detections were found in a line in Arcadia, Glendhu, Kauri point centennial park, le roys and tuff crater

More analysis is needed on a few of these cards to determine exactly what ‘other’ marks have been found. We will therefore get in touch with Kaipātiki Restoration Network groups and reserve volunteers when we have that finer detail. PFK have traps available for both mustelids and hedgehog - for reserves or for at home if needed.

Possum detections this year were highest in Arcadia, Smiths bush, Akoranga, rangatira and one section of hellyers creek. Note the second version of the possum map has had black spots placed wherever rat chews were high to moderate. This is because rats can cause biasing in the data, as they can obscure any marks previously made by a possum. These black areas are therefore unknown this year.

In Summary:

  • A big well done to those volunteers out there trapping/baiting in reserves that have seen a positive result. For those doing so but have higher pest abundances, don’t be downhearted - we can use this information to help encourage others to help get involved, particularly by boosting the level of predator control in the halos. Backyard trapping is crucial for allowing our biodiversity to flourish across the area. We are all on a journey, and on the whole the trip seems to be improving despite a little detour and back-tracking on the way - so keep it up!

  • If you want to help turn a red or dark green dot into a bright green ‘no chews detected’ line - please get in touch with us. Free training is available to enable you to form and join a reserve volunteer team. It’s a great way to get some exercise and fresh air, doesn’t take as long as you might think as we ‘pulse’ predator control - and helps our area hugely. Use our Contact Us form if you want to join a volunteer roster somewhere.

  • If you live near to one of the red or dark green (high to moderate) reserves - please get in touch with us if you would like to trap or bait predators at home. Let’s try and get 1 in three houses trapping to give our birds and other wildlife a chance to flourish. Please visit our toolshed to pick up your free station or trap - all we need from you is a report on what you are catching or bait is being eaten. Easy as.

  • For a visual image of how any particular pest has changed over the past four surveys - please click the link here.

  • Volunteers who took part in the campaign and KRN groups will be sent a copy of the full pest data for their interest in the weeks to come.

  • The predator pulse (November) is on now! Get those traps and stations out.

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