But he fell in love with the sport nine years ago and has not missed a season since.
"I always wanted to hunt in Brazil, but there I never had the opportunity," Mr Costa said.
When he started to date his now wife Kelly Costa, he knew her family liked to go duck-shooting, but he was aware that "shootings weekends" were something to be shared with close friends and family.
He was very happy when his father-in-law, Garry McNatty, invited him to be part of his group.
"I felt really special because I felt I was part of the family.
"I never missed a season ever since. For me, it is a good social event, a good get-together ... It is a bonding time."
This year it was even more special for him as he had his son Leo Costa (9) at his side shooting for the first time from their mai mai at Mataura Island.
The boy used to visit his father and family in the mai mai after the day’s shooting was done.
"It is quite fun," Leo said, proudly holding his ducks.
Mr McNatty and his son Dion McNatty were happy and proud to have both Mr Costa and Leo at the mai mai, sharing such a New Zealand tradition.
"When he [Alberto] first started to shoot with us, his English wasn’t overly good, so we sat in the mai mai trying to speak with each other," Dion McNatty said.
"Every year, it gets better and better till we get full conversations 11 years later."
His father agreed and highlighted the importance of the sport not only for socialising but also as for pest control.
"It is absolutely lovely [to have all his family together] ... We just get together and have a really good weekend.
"The thing about duck hunting is ... we have to do it to get the population of duck down — otherwise they spoil the land for the farmers. It is not only a pleasurable thing, but also helps on the population control."
