Hunters shot slightly fewer birds and spent less time in the maimai on opening weekend of the game bird season in Otago this year.

This was despite strong mallard and paradise shelduck trend counts before the season opened, Otago Fish & Game officer Jayde Couper said.

"Fine weather played a major part in the opening weekend success rate being slightly down,

"The good news is there are plenty of birds left for the rest of the three-month season," Jayde said.

Fish & Game has been surveying hunters for 30 years to gather information on activity and success over opening weekend and throughout the season.

This year Otago’s average bag on the May 7-8 opening weekend was almost 12 birds, including mallard, grey and shoveler ducks, paradise shelducks and black swans.

Total bags were down slightly by one bird compared with a five-year average.

"Mallard bags averaged eight birds, almost two below normal," Jayde said.

"But parrie bags were up by almost a bird per hunter."

Duck hunters spent an average of nearly 11 hours in the maimai on opening weekend.

This was about an hour less than normal and could be explained by fewer hunters heading out on the Sunday, Jayde said.

Less than one percent of hunters reached their daily bag limit of 25 mallards.

But the number of hunters who went home with at least one bird for the table was up on previous years.

Long-term trends gained from the harvest survey help ensure regulations are set appropriately to support sustainable game bird populations.

The mallard season is open until July 31.