That is very cynical. I could counter your comments by simply saying you could have an emotional attachement to the ongoing use/sale of such decoys by aquaintance. I can happily say without knowing either Cocks or Williamson - they have most likely done some investigations with the intent of improving the resource for all. They haven't taken a position to protect their own hunting or anything so selfish I'd suggest.
There is a line of thought that mechanical decoys cause over harvest in the young population resulting in an ageing and less productive breeding population over time. This has been studied. States like California ban the use of flappy ducks until a set time in their season when the migratory ducks arrive in order to protect their resident duck population. Perhaps they have a few misguided emotional councillors also?
There is no correlation between declining duck populations and mechanical decoys in NZ because it hasn't been studied.
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