Mouse Plague & Huge Trout

Every 5 or 6 years, a mouse plague explodes in the beech forests of New Zealand. These plagues are driven by the simultaneous seeding or flowering of the native New Zealand beech tree. This produces a glut of seeds or nuts that the rats & mice feast on. With rodents producing 10 offspring every 8 weeks, the plagues can eventually do a lot of damage to the native wildlife, especially as the seed runs out and the mice and rats turn to other food sources.

However, for anglers there’s a silver lining. The millions of extra mice move around looking for food and shelter, and in the process many are forced to swim across the rivers to forage for more food. Trout, being the opportunist feeders they are, soon tune into the large bundles of protein available to them and have no hesitation in walloping them at every opportunity! With such an extraordinary amount of extra food for the taking, it is easy to see how a 5 pound brown trout can become a 7 pounder in a matter of months. At the extreme end, I’ve seen mouse feeders that ‘should’ be five pounders but weight nine pounds. The fishing techniques we tend to use on a “mouse feeder” are pretty much the same as usual. The mice are mainly eaten at night, so thoughts of fishing mouse flies Alaska or Mongolia-style, are largely misplaced. The excitement is all about the incredible size and condition of the trout.

As you can imagine, mouse years are predicted by fishing lodge owners about as often as snow resorts predict a bumper year! However, what’s different about the latest prediction is it’s offered by Department of Conservation scientists. Here’s some of what DoC says: “The heaviest beech forest seedfall in more than a decade is predicted in 2014. It is expected the increased seedfall will lead to an explosion in the numbers of rats, mice and stoats… Beech trees generally seed every four to five years but weather conditions over the last two summers – a cool summer followed by a warm one – appear to have triggered a bumper seed or ‘beech mast’ event…

Past experience has shown that when a beech mast occurs, it leads to a dramatic rise in mice and rat populations, who feast on the plentiful seed all winter.” Read more. So, whilst I’m not guaranteeing a mice plague, it would appear that the scientists are saying that it will happen. If you want the best crack at a 10 pounder, then this upcoming season may be the one!

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Feb 5 2016

Having just returned from ORL for my third season of fishing there, I can only reaffirm that this place is fabulous! Felix remains the absolute star, advising on my angling… Read more

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Mar 23 2016

This is the place - if you have ever dreamed of fly fishing in New Zealand, Owen River Lodge is it! From the moment we arrived, our host Felix made us feel like old friends. Our… Read more

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Awards & acknowledgements

Owen River Lodge NZ: “Fly fishing at its very best”

Ph: +64 3 523 9075 Address: Owen Valley East Road, Murchison, Nelson, South Island, New Zealand