The number of ducks shot on the opening day of annual waterfowl season in southeast Australia is correlated with the SOI some 2 year prior to the season (Norman and Nicholls, 1991). Apparently, heavy rains (which often follow an El Niño-related drought) result in widespread floods. These fill ephemeral wetlands, leading to enhanced waterfowl breeding (few species breed on permanent waters). In the following year, as the post-El Niño floods recede, the waterfowl congregate in the permanent wetlands, thereby leading to inflated numbers. An increased harvest ensues in the next open season. So, an El Niño, with low SOI, tends to be followed about 2 years later by an increased duck harvest.
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