Kiwis called upon to spot the pigeon

The annual Great Kereru Count will help scientists around the country to build up a comprehensive picture of where the native wood pigeon is and isn't found today. Photo / Tony Stoddard

Spot the pigeon - that's the aim of a week-long survey opening this weekend that will harness "citizen science" to grasp whether our colourful kereru is becoming rarer or more common.

The annual Great Kereru Count, running from this Saturday until next Sunday, will help scientists around the country to build up a comprehensive picture of where the native wood pigeon is and isn't found today.

Last year, more than 7000 people took part, counting around 14,000 kereru across the country.

Kereru, one of the largest pigeon species in the world, is known as the "gardener of the skies" because of its important role as the principal disperser of seeds of larger fruiting plants, such as the karaka and taraire.

No other bird is large enough to fulfil this function, making the species essential for forest regeneration.

Victoria University ecologist Dr Stephen Hartley said the central question of the survey was whether the kereru population was growing or declining.

"Given the ecological importance of kereru, this information is critical not just for protecting this species, but protecting our forest ecosystems for future generations."

Dr Hartley said there was anecdotal evidence of kereru numbers increasing in Wellington, although it wasn't clear why this was.

Taking part in the survey required Kiwis to count kereru in their backyards, schools, parks and reserves over the period and report them to the official website.

The data will also be collected and stored on the NatureWatch NZ platform.

"Whether you see any kereru or not, sharing your observations with us will help build up a clearer picture of where the birds live, how many there are and what they eat," said Tony Stoddard, WWF's Kereru Count Co-ordinator.

"They are distinctive looking birds; their large size and bright white, green and purple plumage make them easy to spot perched in tree tops or on power lines."

In this year's separately-run Garden Bird Survey, a total 1667 kereru were counted, including 253 in Auckland, 184 in Wellington and 189 in Dunedin.

• Information on how to take part in the survey can be found online at the website www.greatkererucount.nz. Counts can also be made via the iNaturalist app for android.