There was not only an increase in duck numbers but also gun licences which were up between 10 to 15 per cent compared to 2019 nationally.
"The population trend counts that I've seen, numbers are up about 10 per cent in places like Otago, Taranaki a bit of Canterbury."
He put that down to a good breeding season; which saw good amounts of consistent rainfall in key areas over summer.
"The last couple of months we haven't had much in the rainfall department but during that juvenile period there was consistent rain, so there lots of habitat for them.
"It's not super damp but consistent rainfall, keeping water in ponds and things like that."
He also knew there was concern from duck shooters about the delays by police in processing their licences.
"There's delays with police and the relicensing department so we're obviously concerned if people haven't been aware of that.
"A stat I saw the other day; about 40 per cent of firearm licence owners were only putting in for relicensing just before it expired, like the day, or a month before but police are saying you should be putting aside four to six months for relicensing.
"The numbers concern us but we haven't able to quantify how much of an impact that has been so we're just telling people to check."
If they were busted, it would put an end to their season, he said.
"We don't want someone to be caught out and have their duck hunting interrupted because they can't legally possess their firearms because their licence has lapsed ... we want people to be able to participate."
Fish & Game and police did joint ranging duties in many key duck shooting areas and Cosgrove said he just wanted duck shooters to avoid any "uncomfortable discussions".
Asked about any shortages of duck shooting ammunition, Cosgrove said most supplies seemed okay.
"Certainly on 12-gauge I haven't seen any supply issues with that and that's 90 per cent of the hunting.
"I know Hunting & Fishing and Gun City ordered well early. They were on the ball last year ordering very early."
A spokesman for Gun City said that while there had been a "little bit of a supply issue" with ammunition, they were well stocked as they got theirs in from Spain.
He said most of the shortage was supplies coming from the United States.
That was attributed to not only shipping issues but also the US election, which usually saw Americans panic buy in anticipation of possible changes by the new, incoming government.
Hunting & Fishing NZ chief executive Darren Jacobs agreed there were "pockets" of shortages at "the odd store" but it wouldn't affect anyone being able to go out over opening weekend.
"There are pockets of shortages but I wouldn't take it as anything potentially serious that would stop a hunter from going shooting on Saturday.
"The 20-gauge ammunition had been running low, and that was due to a combination of factors, including changes in regulations, there was also much higher demand, which had created a bit of a shortage, as well as Covid and shipping difficulties.
"I wouldn't rate in that it would stop any hunter hunting this weekend."
Act's Fair Firearms Law Reform spokeswoman Nicole McKee said "thousands" could be affected by the "unacceptable delays in processing firearms licencing applications".
"Figures obtained by Act show thousands of people are waiting months for both new applications and licence renewals.
"Police have said the most helpful thing to do is apply four months in advance, but the figures we obtained show almost 5000 applications have taken longer than six months and 1382 have taken 12 months or longer."
McSkimming said its new processes, coupled with the impacts of Covid, and demand for licences, had led to the delays in processing.
"We appreciate people's patience and want to assure applicants we are working on solutions to reduce the pipeline of applications."
