The Arthur Rylah Institute for Environmental Research's official report into abundance estimates for game ducks in Victoria has been released. You can read the report here.

This data is likely to be extensively misquoted, however the important features are:

• This count/survey method is still very much in development and is only of limited reliability;
• The survey noted a 58% increase in water area in surveyed water body types - but EXCLUDED temporary wetlands and flood water that was present during the survey;
• Small streams and irrigation channels are also EXCLUDED from these surveys due to difficulties estimating water availability in channels accurately, and difficulties surveying small streams;
• Shallow temporary wetlands and flooded paddocks were not considered at all in this year's counts and estimates. These areas are highly productive and preferred habitat for ducks, and there was a huge amount of flood water present both in Victoria and the greater Murray-Darling Basin at the time of the count.

Regardless of the survey not considering HUGE amounts of habitat that definitely held ducks, the survey reported:

• An increase in Pacific black duck numbers;
• Wood duck population was stable;
• Decreases in other duck species;
• Surveyed numbers of hardhead, pink-eared duck and bluewing shoveler were too low for accurate estimates to be made;
• The model-based estimate provided an outcome of an estimated 1,900,300 game ducks – (down from 2,820,800 in 2021); and
• The Design based estimate provided an outcome of an estimated 2,410,000 game ducks – (down from 2,958,700 in 2021).
   

The survey acknowledges: “it is probable that the lower estimates recorded for some of the game duck species could be due to the high availability of alternative habitat, both in Victoria and in the Murray-Darling Basin more broadly. Game ducks occurring on floodplains and flooded paddocks would not have been captured as part of the current aerial or ground survey, which would lead to abundance being underestimated if these habitats were being used to any significant degree. In addition, increased water availability in the Murray-Darling Basin may have resulted in some dispersal of ducks from Victoria, especially for species that have long-range and dispersive movements, such as grey teal and pink-eared duck (Roshier et al. 2008).”

The model identifies and explains several recommendations for increasing the accuracy of future surveys and estimates.