Kia ora, Anyone know of any NZ research into whether owls or other creatures are being affected by eating rats or mice who have died from ingesting bait, please?
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I couldnât find the exact paper I remember reading recently (yet), but here are some other results I got from a keyword search using variations on âsecondary poisoningâ âbirdâ ânzâ, which should provide a starting point.
- Anticoagulant residues in rats and secondary non-target risk (doc.govt.nz)
- The toxicity and sub-lethal effects of Brodifacoum in birds and bats (doc.govt.nz)
- Review of the toxicity and impacts of brodifacoum on nonâtarget wildlife in New Zealand - Eason - 1995 - New Zealand Journal of Zoology - Wiley Online Library
- Trends in vertebrate pesticide use and development: alternatives to 1080 - what and when? (envirolink.govt.nz)
- Estimating impacts of poison operations on non-target species using markârecapture analysis and simulation modelling: an example with saddlebacks - ScienceDirect
- FATE OF MOREPORKS (NINOX NOVAESEELANDIAE) DURING A PEST CONTROL OPERATION ON MOKOIA ISLAND, LAKE ROTORUA, NORTH ISLAND, NEW ZEALAND
- Diet of moreporks (Ninox novaeseelandiae) in Pureora Forest determined from prey remains in regurgitated pellets (nzes.org.nz)
- The ecology and breeding biology of morepork, Ninox novaeseelandiae, and their risk from secondary poisoning, in New Zealand (massey.ac.nz)
- Higher call rates of morepork, Ninox novaeseelandiae, at sites inside an area with ongoing brodifacoum poisoning compared with matched nonâmanaged sites - Fraser - 2008 - New Zealand Journal of Zoology - Wiley Online Library
- A review: poisoning by anticoagulant rodenticides in non-target animals globally - PMC (nih.gov)
Adding a bait name or bird species to the search tends to bring up more relevant results as well. Would love to read other recommended research, especially any other review papers 
Thanks Christina, this looks v interesting. Iâve read 2 so far and my knowledge is already growing. Its really Morepork that concerns me from secondary poisoning. We have only just started seeing owls again in this part of suburban Auckland after several years of baiting. Diphacinone has much lower risk profile.
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You only need to look at what happened with the Bald Eagle population in America after poisoning Wolves etc. The Eagle population plummeted to to a point of almost extinction. Once poison was outlawed the population is now back to pre poison populations. The same I imagine is happening to the Owl population
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One of our team reports from his farm near Auckland that he leaves carcasses of trapped possums and trapped rats out in the fields.
Hawks come to eat the possum carcasses.
Hawks however wonât eat the rat carcasses and this is without poison.
Wild cats wonât eat the rat carcasses. The carcasses just rot.
We use brodificoum for control of rats n possums at a landscape scale.
We regularly have ruru outside our windows at night, our kahu population is doing very well, too well.
Thats not a scientific slam dunk, but another anecdote that removing the rats n possums has a positive effect on the things we care about.
As we take out the consumers of brodi pellets, our bait take trends to zero. This is even better for ruru & kahu.
Come 2050 when all the introduced mammalian predators are swept from the land, weâll have no need for any brodi, or 1080, or other horrendous toxins. Job done.
Thank you very much, Paul.
So far, the evidence is pointing towards no secondary poisoning.